85 Z28 with 350 rebuild, 305 heads and 305 TPI setup. I have stock injectors and ECM, fuel reg. and so forth. Anyways looking to put in new injectors. What size injectors should I use 19, 22, 24. What else would I have to upgrade now. The guy that did my motor has the same setup and his 350 runs great. Any guesses?

 

F1,

What other changes are happening? Those 305 heads are going to be a little restrictive, so I'm guessing that you are planning on a different cam for the build. What are the cam specs?

If you are planning to use stock 305 heads and a mild cam, the 19 PPH injectors are probably going to need a little higher pressure to feed the 350, but are a good match for the heads. If your cam profile is going to be compensating for the small stock heads, you'll need to consider at least 22 PPH injectors.

Personally, I would try to find some different heads with small chambers or plan on some serious porting for the 305 heads. Don't forget that you can increase the valve sizes if the heads are going on a 4" bore block - just watch the valve shrouding at the perimeters. If you increase tha valve sizes and unshroud the chambers, you'll have to consider all the factors before deciding what injectors to use. For maximum power, larger injectors at lower pressures seem to work a little better than the reverse.

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Vader
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The cam that went is 270 comp cam. All new valve job, porting, and valve springs. The motor was dyno at 280hp on a bench dyno. The head job was all pro done. Do you think that the stock will work with this app.?

 

stock could work so long as you put an AFPR on it set about 52psi. otherwise no bigger than 24lbs will be fine. you will need new chip to correspond with the injectors. of course to optimize what you have you need another chip anyway.