Intake and carb choice. Holley or Edelbrock. Stall convertor

[piecesparts]

If you were to spend time running the 750 CFM carb on the street for daily driving, you will probably find that the acceleration to be a little sluggish. That is UNLESS, you are running the RPMs up and then launching the truck. The reason I say this, lends to the weight of the truck compared to something like a Camaro of the same era. The 750 will perform really well on a lighter vehicle and give you a great driving ability in traffic, but on a truck, the 4000 lbs in your truck will tend to load up your carb and make it run different than on a car. ALso, while you are loading up the engine, you are plating out material from the gasoline on your intake valves and making them less efficient.

If you discussed this with any of the carb manufacturers, they would tell you that on a heavier vehicle, the smaller CFM ratings give a faster air charge to the cylinders and thus give you a better low-end torque. Holley/ Edelbrock/Carter/Demon---all of them will talk the same in this area.

Now if it is your plan to run the truck on a track at high speeds, then you could justify the use of the 750, but daily driving, the 650 is a better size choice. I am running a 650 on my 84 GMC SWB/383 stroker/comp roller cam/700R4 tranny/3.73 gears truck and it works fine on the street. It even gives me a decent 15 MPG gas mileage for a heavy truck that when I travel is loaded up in the bed. I had a 750 on it for awhile and I have experienced the lazy/loaded up performance that can come from a bad combination. The Quadrajet design is the best (small primary bores and larger secondary bores) is the best combination of them all. However, the choice is yours. The only real noticeable difference between the 750 and the 650, other than the street driving capability is the top end on your acceleration. The 750 will let you rev the engine higher, where the 650 will limit the acceleration by the amount of air flow. I can tell you that I have seen the point on my speedo, where there is no more numbers and the guy next to me said his speedo was above 125 MPH. So the 650 is good for that much effort. I call that the OH WOW section.