I have a 72 stingray with a 350 that i purchased last year and i just had it rebuilt , when i picked up my car from the shop the mechanic said that the engine runs real good , but it has a holly 650 double pumper and it just pumps too much fuel for that 350 , he told me i could stay with a holly 650 but a single pump, like you it was fine at highway speeds , but if you put your foot into it from a stand still it would stutter, thanks,Larry

Another point to consider is the volume and length of the intake runners. A longer runner has better low end torque. The short runner is better for high end. So the dual plane manifold is usually better for normal street driving. The single plane will provide better top end, but again at the expense of the low end, which is where most of us drive.

The same thing that make headers work will affect the intake as well. An object in motion tends to stay in motion. When air is rushing down the intake the intake valve closes and the pressure at the valve increases to greater than that in the main manifold chamber. This causes the air to start up the manifold the other way. As it does the same thing happens in reverse. Now the pressure in the intake is greater than the runner and air starts to flow down the intake runner again. If the valve opens when the air is returning the volumetric efficency go up, and you get more air in the cylinder, thus more power. If the valves opens when the air is going up the runner, the air has to stop and reverse direction, which starves the cylinder of air. The key is the length and volume of the intake runners. Due to time between valve openings, the longer runner works better at low RPM. The shorter one is better at high RPM. The volume also plays a big factor. If the opening is too small, the air is restricted. If the opening is too large the air does not move fast enough, and the rapid movement slows down and cancels the effect. If you chose correctly it acts like a super charger and increases the amount of air in the cylinder. This is why the right manifold for what you want to do is critical.

The carb design also has a lot to do with it aside from CFM. A Q-jet has a very small primary and a huge secondary. The Holley has all bores about the same size. A carb is most efficent at wide open. The further open it is the better the air flow responds for fuel atomization and response. The smaller primaries on the Q-jet allow better low end operation and response then the larger primary bore of the Holley. So for most normal driving it is a better responding carb, and delivers better mileage. When you do want a lot of fuel the huge secondaries open and give it to you. BUT.. The difference size of the bores does not give equal fuel charge to all cylinders. The rear can get more air fuel than the front cylinder. This means total performance can be a bit less than the Holley, which has even size bores, and even fuel deliverly.
This means the Holley is better for flat out running and racing, the Q-jet is better for low end throttle response.
Now with a larger CFM carb in either case, the primary bores are not open as far at low speed, thus not as responsive.

I prefer my Q-jet and dual plane manifold for the type of driving I do. That may not be the best choice for you. You first must ask yourself what you want the car to do. I know I will lose a bit on the top or on the strip, but that's not where I will be. Most of us say we want the most, but are not always willing to give a bit to get what we really want/need. Only you can answer that.

Ken Styer

i have a 72 vette w/ a holley 750 manual choke as well.If u want performance like me, i would suggest a holley strip dominator manifold. i have one and mine and it runs like a monster(in a good way that is.)but if u want a daily driver u should get that edelbrock manifold.