New to this forum, any help would be great. This is what I have. 1985 Trans Am with Modded 355 TPI engine. Cam is a Comp Cams 218 duration 456 lift. Roller rockers, Headman shorty headers, heads are cast iron ported polished, decked, bowl cut with 3 angle valve job. Stock distributor with Accel 8mm wires. Comp Cams double roller timing set. No tuning or chip. The car has a hesitation on acceleration at any speed almost acts like a misfire, sometimes you can hear it backfiring through the intake. My question is, are the stock 305 19lb injectors enough for this engine? I have installed a adjustable fuel pressure reg. and set it to about 56lbs. It still acts like there is not enough pressure there. Would the 24ib injectors be better and if I installed them would I have to get a custom tune for it? Thanks in advance for any help.

 

1st off you should have at least 350 injectors (22lb ) and a then contemplate a tune.
The fact you have your FP so high indicates you are not getting enough fuel supply
Higher pressure means injectors spray more fuel every time they open but obviously can only spray
so much which in your case is probably not enough, hence the flat spot

What chip are you using; 305 or 350?
what knock sensor; 305 or 350?

 

I currently have the 305 knock sensor and stock prom for the 305 also. I was reading on here about the 305 to 350 swap and I ordered a new esc module, knock sensor, and now looking for a prom. Anyone know what prom I can use?

 

Oh, I have the injectors ordered also.

 

your best bet is a custom tune.
You can "get by" with a stock 350 chip, fuel PSI @48-50, unhooked Knock sensor, timming set at 10degs .
How is the maf? new? older? dirty wire in it from oil K&N filters?
Sounds like a bad plug, wire, or a over tightened intake rocker.

 

.. Skim through the 'Performance Prom' 'sticky' above for beginners for a better overall view of what you're facing... if you haven't already...