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CARB HELP


Speedracer99

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HAVE CHOICE OF RUNNING STOCK HOLLEY4412 2 BARREL OR QUADRAJET 4 BARREL.... I GUESS

 

THE HOLLEY WOULD BE MORE DEPENDABLE.....? BUT PERFORMANCE WISE? ANY HELP OR

 

OPINIONS APPRECIATED THANKS

 

ON A 355 CHEVY FLAT TOP PISTONS AND 441 HEADS WITH CAST IRON INTAKE

Personally given the choice I would run the qjet. It opens the air dam (and adds fuel thru the secondaries) based on the emgines volumetric efficiency demand while the Holley is a force feeder. Makes a much smoother operation - in short the holley can be dead on at wot from 3000 to 3500 rich from 3500to 4000 lean from 4000 to 4500 and back to right on at 5500 while the qjet is gonna be right all the way (once ya tinker with it some). And a plug check don't tell ya this unless you various checks at various rpm's all a wot etc. The only saving grace I see in the holley is the super easy dissasembly and reassembly when tuning. The qjet you pretty much have to pull the whole carb and work it on the bench (or risk dropping stuff in the holes).

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in my experiance it depends on track.....I have won a TON of races on small tracks with a 4412 against qjets... only on the biggest tracks did I ever wonder if I was losing something...but still won the Grand at HRP with a 2bbl...probably only one in top 10 that night...

 

at the time I ran a motor combo close to what you describe...IMO the 4412 is much more reliable and predictable....unless your running asphalt...or a track that is always super tacky....that is what i would go with....lol

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Gotta agree with A.J.,We did gain power with the Q Jet..However it was VERY unpredictable..On the tighter , on the gas off the gas the Q jet hurt us...Also we saw a big difference from heavy to dry... So it might be great in the heat, not near as good in the main...And our Q Jet was from one of the best in the state, so it was built right..We now run the 4412 all the time.....Frank t

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We setup and have build Q-jets and for what it's worth have found there are ways to make them very responsive. There are a few setup things that can be done with the secondary plates as well as the power piston that increase the effect vaccum has on the carb. to make it react quicker. I have built, driven, auto-crossed and drag raced Edelbrocks, Holley's and Quadrajets and while a Q-jet can easily take 10 times longer to setup over Edelbrocks or Holleys the difference can be that big as well.

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  • 3 weeks later...

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