I have a 383 Stroker in my 1989 Iroc-Z. I have the stock injectors still in it and believe it is starving for fuel. I want to put bigger injectors in but don't know what size I should get since it still has the stock fuel pump in it. What do you guys think? 24llb? 28llb? 32llb? In the future I would like to put a new fuel injection system and fuel pump to get more power out of that motor.
Thanks

 

32s

 

Can a stock fuel pump keep up with 32llb Injectors though?

 

Go to Racetronix and get a bigger fuel pump for that 383. When you install the new pump be sure to get a harness or wire it up yourself so that the pump is powered directly from the battery instead of going thru the stock wiring harness. This requires an additional relay. High volume fuel pumps need a dedicated power feed in order to avoid a voltage drop. The stock wiring for the pump is small gauge. You should upgrade it to at least 12 guage. Racetronix and others sell a harness just for this purpose.

 

The stock pump is wired almost directly to the battery, it is relay powered off the battery and switched by the ECM via this relay and the oil pressure sender. there is no need to redo it. It is fine as is

 

Twin Turbo is correct. 4th gens have the voltage drop problem, thirdgens don't.

30-32lb injectors with a walbro 255 pump will cover your 383 nicely.

 

So can I get by with 32llb injectors without replacing the stock fuel pump?

 

I don't know. I've never run 30s with a stock pump. It depends on how hungry your engine is, no one can predict that for you over the internet.

The 383 in my red IROC consumes all my 30# injectors can hose out even with 50psi fuel pressure. The tamer 383 in my GTA gets plenty of fuel with 30s and stock fuel pressure. Both cars have Walbro 255s. I'd guess that the IROC would need more than a stock pump for sure, the GTA, I really don't know if a stock pump would support it or not.