New Carb

[l81c3vette]

Hey there, Ive been having problems with my Q-jet carb such as flooding, irratic idle, stalling, and all kinds of other weirdness. That carb was great as long as you were in the throttle but at a stop, it was pot luck on how it would act.
I just got a Holly 650 double pumper and now she purrs like a kitten and the throttle response is unbeleivable! Its like a whole new car. Ive only had one other car with a holly fuel system and now im a true beleiver!

 

[shaner238]

Was this a simple swap? Just unbolt the old and bolt on the new? My Qjet works good but smokes when you stomp the gas.

 

[Rodney Gold]

Why the double pumper? Vac sec works much better unless you have a manual with a wildish cam or an auto with the same type cam and a high stall and a high diff ratio.
I woulda gone 600 vac sec ..........

 

[shaner238]

Why the double pumper? Vac sec works much better unless you have a manual with a wildish cam or an auto with the same type cam and a high stall and a high diff ratio.
I woulda gone 600 vac sec ..........

I'm not sure what to do----I just don't want the car to smoke

 

[Vettehead Mikey]

Your car now runs the same as when it was new.

 

[shaner238]

any suggestions

 

[Vette79]

Was this a simple swap? Just unbolt the old and bolt on the new? My Qjet works good but smokes when you stomp the gas.

This is not related to your carb. Stick with the QJet.

 

[fine69]

Hey there, Ive been having problems with my Q-jet carb such as flooding, irratic idle, stalling, and all kinds of other weirdness. That carb was great as long as you were in the throttle but at a stop, it was pot luck on how it would act.
I just got a Holly 650 double pumper and now she purrs like a kitten and the throttle response is unbeleivable! Its like a whole new car. Ive only had one other car with a holly fuel system and now im a true beleiver!

Sorry, I'm not convinced. It sounds like your engine or Q-Jet was not tuned properly...

It takes a bit more finesse to tune, but once its done, the Q-Jet is a perfect carb for your street performance Vette.

I'm glad your double-pumper is working well for you right now. I've used a double-pumper before - it's usually not as efficient as a good vac secondary Holley -- or the Q-Jet. You simply don't need that much fuel pumping all the time for the street.

Ralph

 

[baxsom]

a lot of people are always saying qjet qjet qjet but on mine i went through 2 trying to find one that would even idle properly.

i am suree that qjets run just fine when you find that magic one that runs perfectly out of the box or that one guy still left around that can tune it for you but holley tuners are a dime a dozen around here and i have installed 4 now on various cars that ran so well out of the box that it didnt even need a tuner so i personally am just not on the qjet bandwagon yet.

 

[l81c3vette]

The holley is probably overkill for the little bit of engine work that has been done. The deciding factors were the fact that it was cheaper than trying to rebuild a reman carb (with no guarantee on how long it will last) and also it is enough carb to handle any addtional engine work that may come down the road.

 

[Vettehead Mikey]

The holley is probably overkill for the little bit of engine work that has been done. .

Your Holley 650 is 100-150 CFM smaller than a stock qjet.

 

[baxsom]

The holley is probably overkill for the little bit of engine work that has been done. The deciding factors were the fact that it was cheaper than trying to rebuild a reman carb (with no guarantee on how long it will last) and also it is enough carb to handle any addtional engine work that may come down the road.

maybe a little
using the standard carb forumula at 85% VE i keep getting a necessary cfm of 460.

using the carb calculator from thee CAC toolbox it says 550ish to almost 700ish
so a 650 may be a little on the big side but not enough to get rid of it IMO

 

[shaner238]

The car only smokes black when getting on it hard. I figured it to be the carb---what else might it be?

 

[LVMYVT76]

Have the rochester rebuilt by someone that knows what they are doing. I had mine refurbished, which meant it was not only rebuilt but colored just like it was new from the factory. Runs great now, just like when it was new.

 

[6880 Mike]

An excellent reference book. Includes a section on tuning the Q-jet for street/strip.