Small Block & Big Block Chevy Specific - TBI to Carb

What all would I have to change or delete to get a carb setup to work on a 91 firebird that has a 305 TBI? Car runs rich, the 305 block is bored .030 and has a mild cam, don't know the cam specs.

How much HP would it be worth to go from TBI to a decent carb and intake??

You will need an intake for a carb, and one to fit the 87-95 heads , the diffrence between the 87-95 and 87 and older heads is the two center bolts on each side of the intake the ones on each side of your egr crossover they are almost straight up and down v's all angled like the older ones, edelbrock has them in the performer intakes, you could still run your distributor, i have before but they suck go to an hei distributor, you will also have some fuel pump issues everyone i know that has done this pulled the electric pump out of the tank and put a manual pump on the engine other than that thats about it

Thanks.

The 91 birds didn't have HEI distributers??

I'm going to try to figure out if they are the heads from a 91 305 or if they are from 79, the block is supposively from a 79 and its got some GM orange paint flaking off it.

What about the fuel pump though? Pressure just crazy high or something for the carb? I know carbs use way low fuel pressure compared to fuel injection.

every single question you could have about the swap can be found at www.thirdgen.org

just type in tbi to carb or whatever and you will get about a gazillion answers. Just dont post a new "Generic" question about it. That over there that is like asking "whats the difference between a camaro engine and a trans am engine" on here. They will get pissed and tell you to search. good luck :judge:

You don't have to change fuel pumps, just put an adjustable reg on it and bump it down to 5-7 psi instead of 11-15 psi.

i converted my old 88 silverado from tbi to carb(long story short, its too hard to run tbi on a 472" cadillac)

put in a normal HEI and wire its BATT wire to the large red coil wire from the TBI harness, white coil wire goes to TACH terminal on the HEI. ran my fuel supply line to a T, other 2 fittings off the T went to carb, and to an adjustable regulator IN port. OUT port of the regulator ran to the fuel return line.

simple conversion. not a fan of switching EFI to carbs but in my case it was necessary.

I've done the swap too, and what patgizz said is accurate. It's a simple conversion. Just grab a return-style AFPR and a HEI distributor.

Ben T.