coppercutlass

As my sbo build is done and ready to add carb and distributor etc. Im kind of having a hard time figuring out what i wanna do. Im thinking the quick fuel 750 vac. sec. clayer series which is only 20 dollars more than a comparable holley but much better. For roughly the same price send in a q jet to smi or one of the other well known carb specialist. Or just buy the 750 main body for my 650 double pumper. Im sure there is guys on here who have tried all kinds of carbs i want to hear your experiences. The build is a .030 350 with 6 heads with 2.072 in. and 1.63 ex. valves w/ just bowl work. 10 to 1 compression , rpm intake, howards cam 512 /512 lift 224/237 if i remembered right. headers, x pipe, probably gonna go with a custom ordered 2600 stall converter. It's dual purpose street/strip driven to the track 50 miles each way.

380 Racer

A Q-jet is hard to beat on the street. For performance a Holley hands down. Quick Fuel, Pro Systems, or any others just tweek a stock Holley. If you know how to tune, you can do the same. I have seen some do worse than stock. I helped a friend with an Edelbrock carb once and ai wouldn't have one of those stuck up your *** . All JMO.

coppercutlass

I'm thinking the quick fuel will be my best bet. I'm ok a tuning not best but it aint the worst nothing a little trial and error won't fix. Some guys swear by q jets It's very tempting as I like to think outside the box. I think car craft tested a q jet vs holle vs quick fuel. All carbs under 300 bucks and the q jet held it's own very well.

olds 307 and 403

Unless the idle circuits are modified on the Qjet, go Holley. I have a decent Qjet but probably won't idle worth a **** without mods, when I upgrade my motor. Seems a well tuned Holley is worth a few tenths over a tuned Qjet.

coppercutlass

yeah . Im probably going to go with a 750 quick fuel slayer it's only 299. before i buy it im trying out my friends 750 holley to see how the engine likes it. My 650 double pumper worked great box stock on my old combo just a slight heistation off idle not enough to make me wanna address it. I was considering the main body conversion because it's cheaper and does away with the choke tower which i never use a choke. My only question is a 750 dp too big or should i get the vac. secondaries.

Rickman48

I've had very good results with a 780 VS - only went through it about 4 times!
Buy one of those Holley tuning books - they really help!
Car went mid 13's and got 13-18 MPG, but with leaded gas.

coppercutlass

i do have the tuning book's i have gotten pretty good at poking around through a carb. I have rebuilt several carb's with no issues . I just havent done extensive track tunning. I usually tune the carb to that it can idle. i do a ten minute idle test overkill but it has happened before. Then i make sure w.o.t. from a stand still works, then from a preload, then i test crusing and part throttle. i have never made carb changes at the track other than adding a spacer. I usually just like to leave the carb where it's at once i got it right.

captjim

I have a 770 Street Avenger on my 355 that is very similar to yours. Runs great, very easy to tune.

coppercutlass

I was considering the 770 . But the price tag between the 770 and the 750 3310 or the quick fuel slayer is over 100 dollars. I re read the article. The holley 3310 pulled the best avg. hp. They did not test the 770 but they had the holley 750, the qf 750 . a q jet 750, a summit brand old holley 750 design. the quick fuel made the most hp, the q jet followed in 2nd, the ebrock 3rd, the holley 750 4th. I think for what i want the 3310 holley would work great. Since a good friend of mie has one we already talked about him letting me borrow it to see how it works out. Since i did tune his carb he is willing to let me mess with it with out fear of messing it up. I also might add to anyone looking for a carb go to holleyperformance on ebay you can usually pick up carbs dirt cheap . I picked up a reman certified 650 dp for $260. If i do come a cross a 770 on there at a fair price i will scoop it up.

SBORule

What ever carb you go with, make sure it has jet exstensions on the rear jets in the rear fuel bowl.

It's hard to beat a 750cfm carb.

I had a 800cfm double pumper holley on my 355 20 years or so ago, it ran excellent too.

I have always run a double pumper with mechanical secondaries, the vacuum secondary carbs I don't believe have an adjustable metering plate on the rear.

My carb has four corner idling, I closed up the butterflies on the rear so the rear idle circuit isn't in use, cause I always had a very rich idle otherwise. You really don't need 4 corner idling on engines without a really radical mechanical camshaft.

Just my 2cents.

coppercutlass

With my holley dp i need to crack open the secondaries so it would not idle pig rich but its just 2 corner idle circuit . Same with my old proform 650 dp but that was 4 corner . When i had just the primary idle opened up on the holley it exposed too much of the idle fuel transfer slot and it idle really rich. I tried everything to get to idle on just the primary side with out having to either buy pre drilled throttle plates or crack the throttle plates open. It idles very well now even on my 307 all i had to do was turn down the fast idle and it purred like a kitten.

SBORule

Oh, I read somewhere were you said you were going to go with a 2800 stall convertor, I would go with a 3500-3800 stall, you'll be happier and loose convertor help with detonation issues too on the street.

When I use NOS with my 3500 stall convertor, it flashes to around 4400 rpm's where our engines make peak torque.

Make sure you get one with anti-ballon plate.

coppercutlass

hmmmmm i might just try the convertor i had in it before roughly a 3k stall. But it sucks on the street too much slippage for my liking but it did launch awesome when i was testing it in the alley behind the shop. I need to have that converter checked out. before i had the 307 in there i had that 3k stall which was suppoused to be 2600-2800 stall . it had a really sloppy feel all over the place except on the launch . it would seem to slip when i down shifted, and on the higher rpms under load.

SBORule

None of that makes sense to me but if it's working for ya, good deal.

coppercutlass

I went with what the book i have said and it worked out. Im a trial and error guy lol. i spent countless hours to get that 650 to where ireally liked it. If you say a 750 dp works good i may just try the proform 750 main body.

SBORule

OK, I see what you were saying, the wife was calling me for dinner and I didn't have enough time to digest what you said.

Those Street Avenger series carbs had some of the emussion holes eliminated in the metering plates to make them easier to tune for street cars. I can't remember what else they did to them besides making them shinny but I know I wouldn't want to buy a dummy downed carb like a Street Avenger.

I don't know anything about the QuickFuel carb you mentioned but the price tells me it's not their top of the line carb.

The ProForm Center section might be a good way to go if you are comfortable making the mods, I'd say do it, the experience would be worth every dime.

If the 650 is a good working carb, why not just use it as is, establish a baseline tune, go to the track after you put some miles on the engine and then do the ProForm swap and see what kind of improvements you gain, just thought.

coppercutlass

One of the local olds guys did the conversion. On a higher cfm carb and from what I remember it picked up some. That is a good way to probably go about it. Get a baseline. Make changes and see what happens. I like tinkering with carbs which is why I'm drawn to the conversion. The quick fuel just has a lot better features than the standard 3310 .like adjustable air bleeds, easy adjust vac. Secondaries which I think are with a screw not too sure. Fully aluminum. Just a really nice imprvement over the 3310 but if it's like the proform 650 I had which quickfuel makes it was jetted wayyyyy diffrent then a holley . In my experience the 650 proform acted way bigger than the 650 holley and it was jetted wayyy richer than the holley. This is one of the reasons I'm kinda on the fence over the quickfuel. I been there it turned into a money pit and I bearly broke even when I sold it. A local speed shop counterman ( older guy ) "told me for most street strip combinations box stock carbs should be close if picked properly if you have to jet it up ur down more than 2 jet sizes to make it work you picked the wrong carb. " Now i understand by todays standards a 9 sec ride can be a street srtip deal but i think he was talking more or less along my lines of street strip . I know higher hp cars require much more tuning .

Rickman48

When I built that 780, [it was the old 3310] I also bought the dual inlet conversion kit, which gives you the rear jet plate, a secondary spring kit, 95cc accelerator pump, a pump ramp kit, 3 sizes of squirters, and about 10 different jet sizes.
Once built, never gave me any problems whatsoever, even during all the changes.
Cam wasn't huge - .505 lift, 284 duration, 108 C/L, 4 degrees advanced.

SBORule

So which carb are you going to go with now that everyone has a different opinion?

coppercutlass

Im going to base line it with the 650 dp. then buy the 750 proform main body . I like messing with carbs like i mentioned earlier so i do like the challange .

SBORule

Sounds like a good plan.