Before putting the new 1904 Holley Street Demon on my engine I wanted to tear it down for inspection and to make a few changes, before putting gas in it mounted on the engine.

It looked both pretty and odd inside, as it shines brightly, but I notice the floats were sitting at 2 different heights. And just like the Thermoquad they are suppose to be equal at about 29/32 to 1 inch, from the top with the gasket on to the highest part of the float. One was closer to 1.250- to 1.5.

The lower one I found hitting the accelerator pump round housing that sets next to it, and sticking to it. When they machined the large hole in the pump housing through it they left the large jagged metal edges sticking out. I will have to grind them off the pump housing, and will grind it flat some there, for more clearance for that float.

OK, examining more I noticed on the primary jets, some brass showing through the hole in the jet under it on one of them, but not the other. So I pulled that primary jet out, and it didn't want to spin out easily for a few turns, when broken free. I get it out and see a brass tube off center and possibly mangled a touch on the end from the jet being screwed in, with the tube off center. So need to center the small tube, by gently nudging it over, and then screw that jet back in.

It might be a good idea to do, with any new carb.

 

yeahs its to bad but your right anything you can take apart and inspect you probably should, worst case you find nothing wrong...

 

You have to QC everything yourself in this hobby. No matter what brand, no matter what country of origin.
For comparison, my street demon checked out OK.

 

Well, I had a few things I wanted to check and change out inside, like with the float heights, and I had a set of new brass floats for a Thermoquad I wanted to see if I could change them out for the fiber ones. But I had doubts the brass ones were made right and not actually made upside down speaking of quality control. And sure enough the arm on them was solder on them the reverse of the ones in the demon. The earliest thermoquads used brass floats not fiber, and the fiber ones were known for absorbing gasoline and sinking after 4 to 5 years of usage, and long before gasahol, in the US.

The quality control check I did, once I opened it up, was just normal for me, but then again I had seen this video in the last few weeks also


To me, the Street Demon is a killer carb, at a killer price. Even more so with a few simple tricks increasing it's all out power capability, and long term reliability, like by using brass floats. The brass ones from NAPA should be made correctly, for the early thermoquads and should work in the Street Demons.

I also have another idea to make the floats more reliable long term, and that is dipping them in some gas tank sealer, like Por15. The added weight to the floats of the coating should be minor. This is yet untried by me, but I do have a can of the sealer that should be here in a few days. It will take years of actual usage to find out if it pans out and keeps those floats floating.

The most common problem with taking apart the old thermoquads was missing the 2 screws in the top, with one kind of hidden in the choke horn, and then trying to pry it apart breaking the plastic body. The Street Demon also has those, and not just the bottom screws holding it together.

 

I found that the floats in my street demon were the same, one higher than the other. But I certainly didn't have the other issues you mentioned or I wold have insisted on sending it back for another unit. I'm still in the tuning phase, actually moving back to the ignition first, but I've found the 750 to be a pretty great carb. I've never owned a thrmoquad (that I know of) but compared to the Q-jet, tuning the demon is very easy. I went with the phenolic bowl and it solved my percolation issues. I'm still running with the stock springs as I'm pulling a good 14" of vacuum but I increased the jet size (and yeah, now that I think about it, the threads were NOT smooth), decreased the rod size, and added [I think it was the] .050 squirter. But I think I'm running a little rich now (still working on getting an AF gauge) so may go down a size on the jets or up on the rods. My only real complaint would be the price of the tuning kit. It's steep for what you get.

 

Yep the tuning kit is way steep for the little you get, and compared to the old Carter track kits, for the thermoquads which even included .111 needle and seats.

But back in the day, before buying parts, a lot of things were made by people. From drilling jets to drilling the needle seats. The rods were often made larger by dipping them in solder, or made smaller by careful sanding.

Of course, if many carbs of the afb/avs, or thermoquad types were used, by the OEMs there were a wide selection of OEM parts, in the junkyards.

I wanted to run one of the first thermoquads in the early 70s, before Chrysler started using them, but instead bought a 1050 Holley 3 barrel, for my BBC. In the years following I found out how good those Thermoquads were, through Kenney Bell testing or watching the very strong Chryslers run with them. Now that sucky fuel and percolation now a days being a bigger problem, that plastic body gains even more advantage.

Kenney Bell in testing on their W30 442, said the Thermoquad equaled or beat the holley 850 on quarter mile times, and equaled the Quadrajet on idle and drive ability, and fuel mileage. Or something like that.

I straightened the brass tube in the primary, or centered it better and screwed the primay jet back in, with my fingers, and this time it went all the way down without real resistance, until the end. And then I put a wrench on it for a little more snugging.

I am working on the float area right now, and find those float pins are very snug and don't want to move outward without a lot of persuasion. I will take the last float out and take a look to see it looks damaged any, from hitting that sharp metal left behind, from drilling the big horizontal hole in the pump housing. Then I will get rid of that jagged metal and hind the area down on that pump a little to gain even more clearance, for the float on that side.

Of course, if I am going to dip the float in sealer I need them off anyway, and while I am at it I will pull the needle and seats to make sure they are OK. I do have some larger .120 needle and seats for an AFB, but they are smaller in physical size for both. But still, with 2 .097 jets and the larger fuel bowls of the street demon that still beats the one one needle and seat and small bowl, of the quadrajets on flow.

I will probably have to restrict flow on cruising, as compared to yours or stock. I am at a high altitude and probably have a smaller cam than your motor. I am also way lighter, so should need less to cruise. Lean is mean is more than just a saying, on the power side as well and will be looking for more like a 13.1 AFR, for full power. A little lean is better torque and richer is more horsepower, in my view. For cruising I will go to 15 or even 16 to 1, if I can get by with it (no surging, pinging, or running hot).

And no spinning the tires, with the slightest throttle. That's down right embarrassing in front of a cop.

 

"but compared to the Q-jet, tuning the demon is very easy"
How do you know that? Have you seen how easy or difficult it is to get a flat fuel curve on this or any other carb?

"A little lean is better torque and richer is more horsepower, in my view."
Really? Do you know what dictates why and where max torque will occur? Do you have dyno info, chassis or engine, to support this claim?

There's so much unsubstantiated info here I don't know where to start. Whatever.

 

Yes, don't listen to any of this

 

[QUOTE=cutlassefi;1198308]
How do you know that? Have you seen how easy or difficult it is to get a flat fuel curve on this or any other carb?

[/QUOTE]

Having the primary rods and springs externally accessible, instead of the secondary, makes tuning daily driving much easier - which in this case, "easier" means "quicker with the carb on the engine". The Qjet makes tuning the secondaries much easier.
So picky.

 

[QUOTE=oddball;1198439]Ok so when you change those “easy” pieces and you still don’t have a flat fuel curve what do you then? With all due respect I think you missed my point.

 

I did the sanding to the Quadrajet secondary metering rods til I found a Rochester part number for the .030" diameter ones.
Rochester had a part number for a .140" or .145" needle and seat for the Quadrajet. I started using those as early as my '68 H/O.

 

Yep, the advantages of OEM mass used style of carb, and the old ways of making what you want. Because of the increase area of the needle and seat size you may have to drop the pressure a bit, to keep it from pushing the needle off the seat. The real secret to increase fuel flow, if rules allow, is probably increasing the fuel pressure on a run temporarily, with an electric pump. I use to pull to the line and stage, and then flip the switch, and flip it off at the end of a run. It works with Quadrajets, Holleys or whatever to feed the monsters.

 

It was also knowing what part numbers to use. In those days you had to make a trip to a GM parts department to order the parts. My wife worked in the business office of a Cadillac-Oldsmobile dealer and would take parts orders in and bring parts home when they came in. I ran NHRA Stock class and used a Stewart-Warner adjustable electric pump.

 

Mark makes a good point, if in a grumpy way By easier I meant easier accessibility to the tuning parts and areas. I've been through several different models of Quadrajets; rebuilding, tuning, using Ruggles' recipes, just to find out all of them were warped to the point of not sealing. And I still like the Q-jet and will probably still build one when I get a chance to make the un-warping plates but some areas are just always going to be difficult when compared to the Street Demon.
But yes, I don't yet know how well the demon will take a tune. But once I have the AFR gauge, I'm hoping to find out

Dipping the rods in solder, I wouldn't have thought of that.

 

Yeppers, having a friendly parts person is handy, and I would hope she was friendly.

While I raced cars, before meeting my friend Ronny Booe, including a 63 pure stock, but most of my knowledge and advancement in knowledge came from a guy 10 years older than me, that also was an Olds dealer mechanic and shop foreman, and built a number of record holding class 442s, for several owners of the dealership here. He then put the first NAPA store in here, with a nice machine shop in the back. But his knowledge of cars and chassis and the rest extended all the way to blown Chryslers and funny cars.

We were AHRA and IhRA racers mainly here, until more recently. Here is even a brief mention on another forum about the Napa shop in the early 70s, and me and Booe. To him, we were legends in the early 70s LOL

https://www.impalassforum.com/vBulle...et-racing.html

If you remember Dickie Harrel it was a Booe's 409 ChevyII, that taught Dickie a big motor, in a short wheelbase car could go fast and be stable. The dogma at the time was the opposite. Dickie was from here and went back to where he was living then, and became famous for his BBC Chevy II Dickie built.

Back to Oldsmobiles. One of the owners of the Olds Caddy house here was a guy named Gene Horn. Ronny built him and drove a solid black 442 coup, with a huge white Rocket on the sides and the Ride a Rocket logo. It was the 3 deuce 400, with a 4 speed. For 2 year,s with 20-40 BBC Chevelles lined up, for that same class the Black Olds always won, for two years straight, and then the car was retired. Some the BBC guys told him they were 427s claiming 396.....

Horn sold the dealership, and got a dealership and a bank in El Paso, but Booe stayed here and built the new owner Clay Burkhart, a new 442 W30 automatic. Once again it won month after month here, with the yoyo Clay driving it.

Ronny then quit the dealership, to open the first NAPA store here, and his own machine shop behind. A few years later Horn calls Booe up from El Paso and wants a new Olds for his teenage son to race. Booe Builds him a 70-or 71 Olds cutlass 350 automatic, for the IHRA racing they were doing back then in El Paso. It held the record for its class and never lost with the kid who knew nothing about cars driving. It was solid black with white stripes and the fiberglass hood option, A set of headers, and some 8 or 9 inch slicks, and other than it looked totally stock. When that car got retired for the new Omega that had just come out I bought it and drove it here on the streets.

The Omega was a Black 350 racing in a new IHRA with limitations such as a 2 barrel, and any OEM heads that would fit (can we say (BBOs) and any compression (11 to 1 flat tops), or cam I think and a TH400 with a B&M 3000 stall. The first run in Odessa with the kid driving was something to behold on 9 inch slicks. All these cars had the factory option 5 to 1s in the back.

But everyone remember I know nothing and am nobody. Anyway Horn after a year or 2 wanted his kid an even faster car, so Ronnie put together a straight 6 chevy, and built and altered chassis for him, with big cam and Booe built a custom intake for it and an automatic. Once again it nabbed the record.

Most, if not all of the class cars he built had an electric pump at the tank and usually a Holley. red or blue with regulators.

I also lived and street raced in places like Tulsa, in 1970 with my 1969 L78 Camaro, while taking flight training, at Ross Aviation. Tulsa was a real hot bed for super cars and bikes then, and my county #6 NM plates gave me away, to those in the racing know there. I was about 22 at the time.

My first official class race I won my AHRA class, and set a new class record. It with my 63 cutlass automatic pure stock. I was 17 and had to give my trophy away to my girlfriend, before going home, since I was not suppose to be racing. My first street race was in a 1958 283 powerpac Chevy 4dr, with a powerglide, and won that one also by the kin of my teeth holding in low all the way.

Losses they happen and teach, if you are paying attention.
None of this was told to impress, but just to give HIM background on who I am, and why or how I know.

I am Nobody and that suits me fine

 

The one thing Mark and I agree with is a good O2 meter, for just about anyone. Its still a rough guide but gives you an idea on whether you are rich or lean here or there.

The little 625 street demon has put out over 500 hp on the dyno, so the 750 should be able to put out more, but how many Olds need more??? Claims of 20 + miles per gallon I have seen, from Olds owners using the street demons with their combos, so great mileage isn't such an issue, with them either

The kiss system. Keep it simple stupid. I have to remind myself of that sometimes.

 

Thanks so much for your thread and the post about the racing history, I thoroughly enjoyed it.

I worked at a hot rod shop 20+ years ago and we sold the Barry Grant carbs back then.

They were usually a good design, but sometimes poorly executed or poorly assembled with no care at times (like yours even today with Holley owning them now), and sometimes they ran awesome right out of the box. I remember the King Demons with the removable venturis, and a few racers did well with them over regular Dominators.

I wish you the best of luck and will be following this thread to see how things progress.

 

Bona fide speed shops didn't exist here in the 60s or the 70s really There was just parts houses and machine shops. The first speed shop I walked into was in Tulsa. I was small and on the main drag I believe it was called Riverside. It had parts up front and a view straight through to a small work area/garage with the owner's Funny car parked in it. There is more to that story but I think I have typed enough.

Tulsa was quite different in many ways. For example the local Chevy dealership retaliate against me for buying my Camaro somewhere else, by taking months to fix it under warranty. Once I changed a number of things and added large orange MT Avengerheaders I knew they would not warranty it further. But I had some small thing, that I can't even remember what fail, and not connect to the engine bay. I decided to see if the Tulsa dealer would fix it. The shop guy said hey pop the hood, and I knew I was dead meat. He said who you are loaded for bear, and I said yeah I guess their goes the warranty work. He laughed, and said no way. Its guys like you on the streets that sell our cars. Race on Sunday and sell on Monday.

I doubt that Barry Grant had a thing to do with the Street Demon, and i think it was just Holley wanting to have something to bury the Edelbrock AFBs and AVS carbs. Though the Street Demon has Demon in its name they might have no real connection to Demon. I have a little chrome skull or two I got of Ebay, with red ruby eyes to glue on the front, of it's black plastic main body. Demon powered

 

Tulsa sounds like a fun place to be in the late 60’s!

My boss owned a successful parts store and full machine shop before starting the speed parts store.



You’d be surprised,,,,, I bet Barry Grant had plans/designs for that street demon already when Holley bought up all that.

Holley isn’t typically proactive in design and innovation ever since the 60’s for the aftermarket. They see some other company or product come out and watch how the market responds, then they make one of their own versions to sell.

If it weren’t for Aeromotive and Barry Grant, Holley would still only make the Red and blue fuel pumps.... their HP carbs would never have been made without companies like Quick Fuel, Davinci, CSU, Barry Grant, and various other custom carb companies modifying Holley Carb bodies and selling them successfully.

They likely wouldn’t have come out with EFI without Edelbrock, Accel, Fitech, and FAST pushing them either.

 

[QUOTE=cutlassefi;1198444]And with all due respect, you missed our point!
It's not reasonable for me to determine, let alone achieve, a flat fuel curve with over-the-fender tuning. So that question wasn't even under consideration!

 

[QUOTE=oddball;1198653]Hmmm I respectfully disagree. For example, I tuned my buddy’s Quick Fuel equipped 440 Mopar with a wideband and handful of jets and air bleeds. We were able to get a very nice curve in about 90 minutes, done.
It’s possible, you just need the correct, quality pieces.

 

[QUOTE=oddball;1198653]Besides this, our methods and objectives might be different from what his are.

When it comes to tuning many were doing it without the advent of computers, AFR gauges, or dynos, and it involved much more than the engine, or the fuel curves. I don't think cheap and easy, or free are in his vocabulary either.

The basic tools for tuning, were the et or timer, the spark plugs, the vacuum gauge, the timing light, and tach. And then experience plus trial and error. We used our brains, with all its sensors to get the job done as well.

To me the greatest tool besides experience and our brains, for maximum power to the ground is probably the ET Timer, of the mid 80s. It just measures speed and distance by time, and was triggered by magnets. The magnets were suppose to be around the driveshafts, but for more accuracy I put them around my front wheel hub. It measured 0-30, 0-60 mph by time, and quarter mile time and speeds, which was all measured out, by it counting the magnets flying past its sensor. For 60-100 dollars it was a very trick device for tuning power, and chassis and weight and how each effected time and where, in a run.

For the other normal diving it came down to plugs and vacuum gauges, timing lights and sometimes dwell/tach meters, and trial and error. Experience was also very handy. More recently we have the widebands setups, to help out on is it rich or lean, for when it bogs or shudders or surges. But they can lie to you and read wrong, and have their limitations.
.
Just passing along what I know or have seen, and I have nothing to sell you.

 

[QUOTE=Firewalker;1198693]I don't know what your backround is but this post doesn't do you any justice. I get you're just stating what you used to do, but I don't understand fighting against modern tech. If you're going to do that then make sure you throw away your cell phone, dump your flat screen TV and every other device you've purchased in the last 20 years.
Here are the FACTS. If you want to screw with plug reading etc then go right ahead. But you won't get the same results you used to cuz of the ethanol in today's fuel. And modern, Quality widebands are extremely accurate and reliable.
I just came back from attending the REC, Race Engine Challenge in Charlotte NC. It was attended by both old school and young gun engine builder/tuners from all over. Not one, I repeat not one was reading plugs for air/fuel purposes. ALL used the supplied widebands, some even brought their own multichannel wideband setups. Why do you think that is?
I get this isn't for everyone. But when you have modern affordable tech a your fingertips that will enhance your driving pleasure AND possibly save your build, I don't understand why anyone wouldn't try to find a way to use it.

Whatever.

 

Hey Firewalker, I have a wideband setup that I can loan you if that helps. It is an Innovate LM-1 handheld.

 

Thanks. I have had for years an AEM Uego controller I bought new off of Ebay, that works quite nicely. In the early 90s I tried a narrow band, and found it almost useless. The same with the first Holley Projection units and they were very unreliable as well.

I have learned that money on tech, by the average person is usually money wasted normally. For example, in the late 1990s when a new computer would cost people thousands, I spent just a few hundred on new parts and built my own, and overclocked the little 533mhz celeron II to over 1 gig, when no 1 gig CPUs were sold by Intel.

I loaded BeOS onto it instead of Windows. I could cold boot to my desktop in 30 seconds and major crashes just didn't happen, like with Windows. The only time basically I rebooted was on a grid power failure. If an app misbehaved just kill and restart the app. It didn't take the system down. Windows cost much more and caused problems an loss of data, and was way slower. And I do love reliable and speed.
Can ya dig it

 

I would be willing to guess that ethanol is the main reason AFR gauges are so popular, now. It's not tech for tech's sake.

 

Definitely not tech for tech sake, but as it improved over decades and the price came way down it became something more practical and useful. It's only real competitor is the 5 gas analyzers, which cost much more and not near so compact.

Its like the first Sun Tachometers, that required a large separate box and huge electronic parts. They failed often and easily, and cost a lot, but over time the price fell in greatly deflated dollars, as practically and dependability shot up. The mechanical tachs driven off Magnetos were much more prevalent in racing way back when.

 

Correct. And as stated it makes it more difficult to read plugs and the ethanol changes stoich from 14.64 to approx 14.1.

 

Just a thought. Why change to brass floats when you can paint the fiber floats to seal them?

 

If you are talking about using a water base urethane the problem is the alcohol content I think. It is gasoline proof but not alcohol proof. The old cork float guys use to use shellac for a coating. Since cork was really before my time, I learned this from searches for possible float costings, since even brass floats can develop leaks, at the solder joints or get cracks in them over time. I just wanted an extra layer of protection. I myself never have had a brass float fail yet in years past.

Getting trash in the needle and seat happened in some and it a bigger problem now with older gas tanks and with alcohol, and while dissecting the street demon design I found small screen filters shoved in the back of the seats, of the needle and seats in it.

On an off topic side note some may enjoy this on soft heads, and notice their opinion towards the end about engines dynos and horsepower.

http://www.theoldone.com/articles/The_Soft_Head_1999/

 

Firewalker, when you get the floats sealed and are happy with the results, post up your process, would you?

 

Be glad to, though for me to be happy with this might take years to say it actually worked the way I liked, and the floats stayed sealed, and the coating stayed on without going gooey, or cracking and flaking off over years.

While Por15 sealer claims to be impervious to alcohol or gas additives in gasoline or what they call Type II fuel, on the can it says resistant. nd that to me is vague and rather meaningless. But just like longevity experiments only time will tell.

But I will post what I found and did on all of it. I just got through messing with the secondary divider plate making sure it was straight and sitting in there properly, which includes clearing the air cleaner stud. I think that plate was flipped backwards in there and was bent to clear the stud. At the bottom of the divider plate there is curve in the center, at the bottom so it can clear the stud. With it flipped backwards that curved part works against you and you would have to V that straight plate to get clearance for the stud hole. I would never have noticed that, if I hadn't taken it apart and got curious.

I know about that plate because I studied thermoquads, and then rebuilt one in the late 90s that came off an early 80s 440 Chrysler and they are similar.
I did get that brass tube under the primary jet back in the right place, and that jet back in. The tiny brass tubes is where the rods ride down into the jets. Racing note. Those running such carburetors on pure race cars may not even use those rods and just jet it for full power, and just ease up through the pits and starting line at idle.

 

My three Demon carbs all had problems like this and more. I got mine just before Barry Grant went out of business so I thought I just got the last of the disgruntled employee models. Seems the quality control issues still persist even under the Holley name.

 

Assembly line mass production, as it is seen today. The last few Holley products over the last few decades I have had problems with for me. Their Projection ecu boxes kept failing for people, and Holley never fixed it and no recall. It was said the control units were made by MSD for Holley. Then again the Injectors are not available for them either.

Also bought one of their new model carbs with the top unscrewing, to expose the fuel bowls, said to be an old Ford style carburetor. The carb after a few years had a bad rep and Holley pulled it from the market. It was all aluminum and the top screws snapped, or stripped easily when tightening them. Summit now sells a similar version of it, but with improvements, for the last 10-15 years.


I would call these more a Holley corporate problem rather than a Demon problem. After all these are not the old Demon style carbs, and Barry Grant sold to Holley years before this carb came out, from Holley.


But I thought its design might be great from knowing Thermoquads and reading the reviews, and waited for a lot of feedback on it from those buying it, before taking the small gamble on buying one. And I am still very happy with it, but I could have design it little better or lot better, from my perspective.


But as they have stated Holley never wanted this to to replace their higher dollar money makers, in sales. I would have designed it a little more like the Thermoquads, with the bolts all from the top. And would have the bar connecting the two metering needles, and the adjustable rod going down to the cam actuated mechanical lift, to lift the metering rods when you gave it gas. I would have used brass floats, like on the original Thermoquads and Holley carbs.


And I would certainly make sure the TV instructions and hole were right.


The original race thermoquads had dual feed and they could also have dual accelerator pumps, and squirters for the secondaries, if needed. Notice 2/3 of a second accelerator pump housing cast into the top of the housing on the passenger side of the Street Demon. But it may not need one, with a small change in the air flapper (2 added holes) pulling the fuel out sooner out of the goggle secondaries.


Overall I think the Street demon is more carb than what Holley wanted it to be, even the way it is, especially at its very low price point.


This thing could make well over 600 hp with the 750, if you are into horse power, and it can flow and make more if they, or you wanted it too or with modifications. While being dependable, and getting great gas mileage putting down the road in your best Clark Kent disguise.

Btw, for those that want to know your fuel level fairly easily, without taking it apart, it is measurable from the outside. A small red spray tube, like used on spray cans, should feed down through the primary jets, where the metering rods would go once they are out, should measure it with the engine turned off. Like checking your oil level.


Just remember don't listen to a word I say.

 

Here is all I did on mine, before bolting it on and hooking it up to run. Took it apart and checked floats and needle and seats.The float setting were off from specs, which are 1.01 inches to the bottom on the floats, or with the top inverted the now top of the floats at their highest point at their corner. Basically the same as the Thermo-Quad. Filed down the jagged edges left by the factory, from drilling the hole horizontally through the accelerator pump housing. Those jagged edges could hang up/stick, and cut through the surface of a fiber float on that side.

I then took the stock floats off, and with POR 15 tank sealer (silver) painted them both with a cheap brush, including where their arms go into them, and then hunk them up to dry. Not much oder noticed from the paint. The directions for gas tanks is to wait at least 96 hours before adding fuel. The sealer dried to the touch, in under 24 hours and had a glossy silvery look. With just one coat some black could still be seen, like along the seams of the floats I considered one coat and this, to be good enough, since the idea is to slow or stop any fuels, from being absorbed by the floats over years, and not centuries.

After a day and a half of drying I installed them once again into the top and checked and set them again, to 1 inch. Never ever bend floats while they are touching their needles. Lift the up off them first. Also made sure they were not twisted any and level, for a straight swing up and down.

As I put it back together I left the green metering springs in it,since only once its running can I determine what I want on them and I see what my vacuum is idling and running around. I also switched out the stock 56/40 (measured) metering rods stock, in the 750s, and installed 60/50 ones, with the same primary jets to lean it out a tad. But how it drives, and what the AFR gauge readings will tell me more, once in actual use. I may need to go even leaner on the rods.

Left the shooters and its top hole arm position on the pump stock, for now. And the secondary jets as well. Did drill two holes about 21/64th in diameter in the upper flapper air valve, to increase fuel being pulled out the secondary tubes faster/ealier at WOT. They will have no effect normally driving around, when the secondary throttle blade is closed, or once the secondary air valve is fully open.

I also oiled down lightly the two teflon seals where the seal were against metal. Teflon is no stick only in the presents of oil. This is why you are suppose to oil and then heat up a new Teflon frying pan first, before cooking anything with it.

 

So, the .01, is that an educated guess or experience? I agree about one coat vs. a second. Just need to seal any porosity. Are you concerned at all that the Por was designed more metal, rather than plastic?
I'll be interested hear your readings once running.

 

The rod change to a larger size is just an educated guess to start out with on mine.I am at around 3,660 feet altitude, and most who bought the 750 street demons seem to jet them leaner. Plus my combo is light weight and probably requires less air and fuel, to get going with its 284/296 cam, in a 461, than some with different engines and combos. Remember this is just to get it running and then I will see how it runs and do have the AFR gauge temporaily strapped to the top of my steering column, so I can see real fast whatever it is running, as too lean or not on light throttle cruise.
I may also disconnect the secondaries, to dial in the primaries first, then reconnect them. If I need a tad more fuel I can sand them down a little at a time. I got one of these a number of years back

https://www.ebay.com/itm/150mm-6inch...4da258f291ed3e

The way I put the coating on the floats it is like a bubble, if you wish encapsulating it all the way back to the brass arm going in them.So even if it came loose it shouldn't be able to come off, by sliding off if still in one piece. The sealer had no real odder of solvents in it, and I puts some excess off the brush on some slick plastic. A few days later I flexed the plastic and the sealer flexed with it. I got a big chunk of the dried paint up with my finger nails and it came right off the slick hard plastic. Which I would expect it to do, but the way it feels and flexes is kind of weird, and more like it is a plastic then say a paint.

 

Hey, where did you put your sensor for the AFR? AEM instructions say "18 inches (45cm) downstream of the cylinder head's exhaust port or turbocharger" but that would put it in the header. I was thinking maybe a few inches after the collector. And of course above the 9 to 3 o'clock position.

 

I have a custom 2-1/2 exhaust, that fits my non Olds chassis, from the cast iron manifolds, and put the O2 bungs a little past the starter area. I have not tried getting my new stainless steel headers installed yet, since I expect it maybe a royal pan and even might not be possible. And my health and time is not the greatest either right now.

How far up the exhaust is a temperature issues, with the O2 sensors, because they need to get up to the correct temp to operate well, or at all. The original narrow band O2 sensors were unheated and really relied on the exhaust heat to heat up fast after starting the negines. The heated widebands are considered less sensitive, to needing exhaust heat placement to come up to operating temperatures faster.

To close to the engine, and you can burn them up, as they would get too hot. Too far back and they may take a minute or two to come on, or reach a good temperature for proper operation. Not a problem really with a carb, in my view, but more of one for injection possibly, that uses them to determine the correct fuel settings.

On the placement and angle, this is decided more by where you have room for it, just think you want any water to drip off it, that might condense on it cooling down, and you want it to not stay on it, in the exhaust pipe. 3 or 9 seems to work fine for me over the years, but I also live in a low humidity area.

 

Right, it's about condensation more than anything. I think I'm good for room but I'd need to know how long the sensor is installed.