the bowl is under the valve . not in the combustion chamber. Im sorry but sean murphy is a guru in the carb area. https://www.smicarburetor.com/produc...ID2/9/sfID3/32


I got time to drink beer after working on cars all day while I relax and watch tv . Just as a fun fact a holley 650 double pumper runs more then 319 any good carb runs close to the 400 range. I was using the sbc manifold example to show that bigger isn't always better.

 

Automatic cars should use a vacuum secondary Holley, this guys car is an automatic and so are mine, 4 speeds are for people who think they are legends, unless you can shift one at 6000RPMs and only lose about 300RPM between shift give it up.
Oh well so I used a Chevy as an example and he said they are not the same so tit for tat.
Unless someone is retired and has weeks to fiddle with a quadrajunk ordering parts, reading books, experimenting and most likely ordering more parts or sending off and paying shipping, its a waste of time, when you can order a carb from summit and be running great in minutes.
(PS) I just threw away 13 quadrajunks with all late 60s numbers because I couldn't get $25 a piece plus shipping out of them and they were in the way of the trash can in the garage!

 

I run a 650 double pumper with an automatic all it takes is a little tuning . I even ran that same 650 double pumper on a 307 with an auto trans. None of that has to do with this so whatever man you win. Go bang gears a 6k rpm and throw q jets away .

 

Not counting full out race engines, a properly built and tuned Qjet has been proven on the dyno and the track to be equal to any Holly. This is fact and cannot be disputed. If one is unable to get top notch performance out of a Qjet then the Qjet was built wrong or it's not tuned right. Yes it can take some work to get it to that level but it can be done. If that makes it 'junk' to some people then that just seems silly to me.

And why anyone would say the 2004r's second gear is 'a dog' is equally silly.....

Is this 270 cam the one with .501 lift, 270 advertised duration and 224 duration @ .050? If so you're recommending this for a 8-8.5:1 CR 350?

One last comment; if I'm giving out advice on engines and my own runs like crap because I selected a bunch of mismatched parts, then I shouldn't expect anyone to take me very seriously. On the other hand if my engine is running ***** out, especially if built with parts that go against what everyone else claims will work, then people will be much more inclined to listen to what I have to say. So wanting to know what someone's car is running at the track is a reasonable thing to ask.

 

I see no reason the OP's QuadraJet carb would not work as-is on his engine without needing any tuning. He's not planning on changing pistons so he can't increase the CR more than a point or so and that's not gonna require any major carb adjustments.

 

He's not planning on changing pistons so he can't increase the CR more than a point or so


after reading everything I'm going to change to dual exhaust, maybe headers and sit tight and when ready rebuild completely to get CR up or look for another engine.

 

The cheap way to end up with a high compression engine is to find a '73-'76 350 shortblock(or complete engine) and put your '71/72 heads on it, along with slim shims. The compression ratio will go up to near-1970 levels.

 

? Why not just use the 72 non window block and get some pistons with a smaller dish. Lots of options. 72 block right? That is a good foundation to start with in my opinion.

 

They don't get windowed until '77. This way he gets a 'proven' lower end.

 

Good grief another thread turned into a pissing match.

 

Why not just use the 72 non window block

What does this mean?

 

Forget about the 350, it's a waste of money. Build or buy a 455.

 

Waste of money or someone just had a bad experience ? I have built some screamers with out a big budget and outdated stuff and I ran em behind th400 to boot which eats up appx. 25 hp . The current bullet should hit the 12's and that's just a 355.

 

Yes but you are building it for 1/4 mile. Your "budget build" involves a lot more than just a budget build.

for a best street engine that makes power at low rpm without a need for screaming, BBO is the way to go.
I have a mighty 355, it makes awesome power from 3k rpm, but it's not enough four the factor.
Even a mild 455 will beat that 355 anytime and be a lot more fun.
I am just saying if you are gonna spend the money, build the BBO and have more hp/tq for $, in the end the cost is about the same but the results are very different.

 

Cutty. I agree a mild bbo would keep up with me or beat my 355 but going to a 455 means better trans too. What guys gotta keep in mind if you want some neck snapping power you will need compression , cam and gear. The more you have to more power your sbo will make . A bbo with probably less compression and cam will be the same but its not a waste imo. Some people think they can have a 400 hp small block and run full accesories and power steering and ac. Well that all eats hp. That's why people get disappointed . I feel stroker engines are a huge waste unless you are doing all out racing. At that point I would go bbo vs sbo stroker.

 

Starting in 1977, the Oldsmobile reduced the engine weight by changing the block casting to remove material in the main bearing web areas. This reduced the strength of the block, so these are not desired for high horsepower, high RPM drag racing use. Many folks take that to mean they are too weak for ANY performance use, but others have built moderately powerful street engines with them and haven't encountered any issues.

Here's a picture of a windowed main web block. Note the missing material beneath the main cap bolt holes.

 

The only real additional cost of a stroker is the cost of machining the crank, an extra $200 and the rods. This assumes that in the "non-stroker" build you would be using quality pistons.

Back to the original poster, who must be pretty confused at this point. As others have suggested, rebuild your carb, tune it up, and put in a 3.42 rear and i think you will be happy with the results.

 

I agree jim ., but you can't stroke an sbo gas block to 455 cubic inches plus the overbore so 461 ish.

 

You can get pretty close with a diesel block build though but that's a whole new ballgame!

 

Yep which is why I specified gas block. Dx blocks are a whole diffrent ball game.

 

I just disagree with your choice of words "waste of time" It isn't that much more and IMO the benefits are significant.

 

I just don't see it for a street car jim. Specially since you gain 105 cubes just going to a 455 and gobs of tq.

 

Following that line of reasoning, then nobody should ever build a SBO in a street car.

 

I wouldn't stroke one. If it came to that I would go bbo before that. For a race car probably dx. I'm not saying don't run an sbo on the street but you. Have to pick and choose your battles for me. I would build a bbo street strip before a stroker sbo. I would build a dx for all out racing. Its one extreme to say to not run an sbo like I said its all bout picking your battles.

 

I don't understand what "picking your battles" means.
"Have to pick and choose your battles for me." is not a coherent sentence and I don't understand what it means.
Just because you would not stroke one does not mean it is a poor direction to go, in fact, quite the opposite. My point was that IF you are building a 350 Olds, doing a stroker nets you more cubes, more torque (faster piston speeds) for just a few dollars more. You end up with a quality build with good parts and a lighter rotating assemble, all for a 5%-7% increase in price. Not a bad investment, IMHO. You can debate the whole 455 vs 350 over and over if you want to.

 

captjim, you forgot to mention, you will also bump the compression up using the same type of pistons, ie: flat top. As you and others have pointed out, this is a good way to get your compression up higher, without doing some crazy dome piston. I see it as a win - win, for minimul investment. Plus it opens up a world of possibilities for rod piston combinations.

 

You can, sure, or use a dish to tailor the Cr to whatever you choose depending on the goals. But yes, all things being equal, with a flat top piston, adding both bore and stroke WILL increase CR.

 

I'm not debatin or saying your are wrong jim. I said my opinion. But who needs an engine on the street to spin up fast if its just a cruiser. The 455 will build enough grunt to move you pretty good. But that's just my opinion jim. You seem to think because I think diffrent I automatically am saying you are wrong.

 

Yes jim that didn't make sense. What I mean to say you have to pick and choose your battles as far as picking what to do with an engine combination. Will a stroker out torque a bbo? 200 bucks ain't chump change that's almost a cam and lifter set. Either way I'm done talking about because its all personal prefrence.

 

davoaz, I have had so much help here from many guys, Specifically copper cutlass, fun71, 70 cutty, old cutlass, mdchanic, olds307 and 403, monzaz, cutlassefi, captjim and many more. My memory is not so good these days.
I have a heavy 1976 olds with a 350/350. Mild refresh only ( not completely rebuilt). The best gains I noticed off the line were from the 3:42 rear gears in which I purchased my rear gears and posi from Monzaz (Jim) TCI saturday night special torque convertor headman headers with full duals.
Without going deep into the block this was the best bang for my $$. The guys have mentioned this in prior posts I see. I would run with doing these things first and see what you think afterwards.
Cheers Eric.

 

The only problem with the 455 which everyone seems to ignore is the added torque which means this guy would also have to get or rebuild the trans mission to stand up to it and possibly the rear end also. That's not what the OP asked for. You guys are all on a rant now and have forgotten the question.

 

I am not on a "rant", issues were brought up and addresses. On this page, several posts up, I posted this,
"Back to the original poster, who must be pretty confused at this point. As others have suggested, rebuild your carb, tune it up, and put in a 3.42 rear and i think you will be happy with the results"

 

Jag you better go back and read I mentioned upgrading the trans.

 

This conversation has nothing to do with the OP's question. Why not just pm each other and argue (have this discussion).

 

OK, I lied, I'm back but it is with something new to offer regarding a friend's 72 small block. He has 3 Olds cars, he & I collaborate on Qjet tuning & modding for friends & aquaintances. He happened to stop by the shop today & I mentioned this thread.

He has a rather clean 72 Supreme that he took to a dyno day w/ Olds club - The results may be interesting & I am going off his memory though he is checking his records as he writes everything down. I'll correct anything that is not accurate but here is the experience.

Initial dyno result = 135 rwhp (tq unknown @ this time). Very disappointing, everybody laughed @ him, etc.

Home he went. Rebuilt the carb, changed jets & rods, messed w/ air bleeds (he says he went a little too far w/ them), curve kit, added more mech, dialed back vac, added dual exhaust.

Went back to dyno - 168 rwhp/229 tq Note - He said he used half the gas that he used on the first trip traveling to dyno shop.
2 months later car ran 15.996@86 weighing 3535# w/ 2.78 rear gears. Was a little lean @ 13.5:1 WOT.

That's one hell of an improvement by dialing things in, helping it breathe a little better & tuning for performance. It's nice to have hard numbers even when disappointing instead of relying on butt dynos or distant, rose hued memories or wishful thinking.

One thing I didn't mention earlier is that I think headers are a requisite addition to any performance build. SBO exh manifolds are pitiful & it is impractical for the average Joe to put BBO manifolds on although I know there is @ least one person on the forums that has but he is a rather advanced builder/tuner so that leaves headers for us unwashed masses. OP had that in his plans & my guess is the car mentioned above might have picked up 5-15 rwhp if he had gone that route.

So I stand by my ideas - add the headers & a good exhaust, optimize & tune what you have, add some gear & traction (ltd slip if not already equipped) & you will really add to the performance of the car. An OD trans is icing on the driveline if it would be in the plan. Source a core engine & build as funds, time, etc allow SBO or BBO is fine, my old 350 ran 13.3 & was easy to live with for "everyday" driving. If switch to BBO, skip the headers for now so you only have to buy them once. Keep an eye on the future as you do things so money isn't spent temporarily as practical, "infrastructure" should be laid to suit the future more than the present. Although in OP's case these basic changes would provide additional enjoyment presently. Who knows, maybe they would meet his expectations enough there would be no need to carry on towards an engine build.

 

Personally when you're building an engine, yes I believe $200 IS chump change. If such a miniscule amount makes or breaks someone's pocketbook then they may want to try a different hobby.

Now this comment is not meant as an attack or insult to you personally copper. Not at all, but damn I just can't believe how cheap some people can be! I understand not everybody has thousands and thousands of disposable dollars laying around to dump into an engine, but if people want to play around with these old cars you gotta have at least some money and if you want a kick *** ride you gotta fork over the dough.

 

Like I said 200 bucks can buy you a cam and lifter set. I'm cheap becausen I have no choice if I had the coin I would just buy everything new. The crrent build cost me a little over 3500 with the cam issue and all that I'm in around 4. If someone had this engine built that arounf the 6k area.

 

To me this guy wants advice on some performance.without going crazy on parts and money .first for me with small blocks is a rear gear change is the biggest bang for the buck.then a real super tune recurve the distubtor rebuild the q jet new plugs wire cap rotor. Then good headers and exhaust. That will ideally get a small block in to the low 15 high 14 .since most stock 350 with highway gears run high 16 to low 17 that is a big power gain for the effort.on a small block if more power is wanted I would have to address more compression ,camshaft,porting ,valves, and using more rear gear.like at least 4.11. If he can get his hands on a 455 a 3.23 gear headers exhaust and a tune.low 14 can be had.

 

To the guys who want to know I have track tested q jet holley and performer carbs on my brother car.jetted and adjusted there was very little difference in performance in the car with in a tenth on a car that ran high 12s