In my 1990 Iroc, I have a 305 5spd TPI with G92 performance package (hotter factory cam; the L98 cam). I want to put in a 350 real soon. Besides the injectors, what will I need to replace? Do I need a whole new ECM, or just a chip change? I have an adjustable fuel pressure regulator so the extra psi, won't be a problem. Any info will be greatly appreciated!

 

Conventional wisdom says harmonic balancer and knock sensor w/module. You can run the 305 injectors with higher pressure - I have a bud who runs faster with 19 lb injectors on his highly modified ZZ3 than he did with 24 lb (he hasn't tried 22 lb yet). ECM is no problem, but a chip does you well even with a stock 305.

You should port your plenum and at least gasket match your intake while you're at it. Exhaust is always a restriction even with the 305, so upgrades there would again benefit you greatly.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

That makes a bit of sense. He can turn the fuel pressure up more with the 19lb injectors getting better atomization than with the 24lb ones. I may try that.