I have a 1986 camaro berlinetta that I just picked up (thank god the previous owner converted it from fuel injected to carb and put a SBC in it instead of the stock V6). Perfect contendor for my recently built big block.

The motor is a 402, mildly built. Forged rods - crank, and pistons, 396 heads, mild cam (486? duration), it's my first real build from bare block. My question is what size carb should I use? I was thinking a 750 CFM was about right, but I'm not sure; I know too big of a carb (from experience of building the IROC drag car with my dad) and you get the same problem as too small of a carb.

 

750 is a pretty good size for a 350-454 really... its the best size for the big small blocks and small big blocks.

 

You take the engine cubic inch and multiply by the maximum RPM and divide by 3456. If you have an automatic transmission you will need a vacuum sec. carb, a standard transmission can use a Double Pumper carb. Although i use a double pumper/mechanical secondarys with my automatic (i like them better) plus i hate waiting for the secondarys to open.
Keep in mind this is just a starting point. But it gives you an idea.
I'd go with the 750.
What brand carb do you want to run?

 

I have a 750 CFM holley carb that I already own that needs to be rebuilt (off my IROC drag car). It's a four barrel and yes the trans is automatic; have a TH350 with a shift kit.

 

Is it Vacuum secondarys or mechanical? It doesn't matter if you prefer one or the other. You can tune either for your application.
Is it a hp holley or old style holley?
A rebuild kit for that holley should run about 30-40 bucks and is real easy to do.
Check the jets when you rebuild it. Being that it was on a drag car and all it probably has bigger than factory jets in it.

 

Vacuum secondary carbs are for tow trucks. Go double pumper.

 

I agree... vacuum secondaries are good for street cars, I liked my 3310, but for the best performace a double pumper is the way to go. The Holley 4779 would be an excellent choice for a 402 (I have one on my 350).