Ok here is the deal, a buddy of mine can pull my 56,000 mile 350TPI in my IROC and stoke it to a 383 for around $500. My question is, can I still run my stock L98 heads and all the intake equipment if i get them ported and polished, which will only add about $100 to the total? If so do they need to be gasket matched? Also with the 383 will I have to upgrade the prom and if so which company makes the best chip for me to use? Another thing....the 383 will probably run about 10:1 and I'm wondering what the CR is on my stock 350? I know right know that I can run 87 octane fuel with no problem and get pretty good performance, but will the 383 run on 87? And lastly will it pass smog? I live in California and obvioulsy it must pass...I plan to leave the cat on it but should it pass? Thanks in advance.

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1989 IROCZ28, 5.7 liter TPI, 700R-4, 2.77 Rear, Gutted Air Boxes, Flowmaster 80 series muffler with dual 3 1/2" tips, Clarion 8575 Head, Infintiy Kappa 4x6 plates, Stock 6x9's, Alumapro 10" Aluminum Sub in sealed box, Orion 400 watt amp

 

Its not really a bad deal for 500 bucks considering the work you need to do to stroke a 350. I suppose you could run the stock heads but you'd be better off getting ones that flow more to feed the bigger engine. You might need a new throttle body, and you could probably replace the TPI base and runners. It depends on how much money you have. If you cant do it right, wait As far as I know the PROM should be changed because the 383 should require more fuel. If it runs 10:1 CR you'll need the top grade gas for sure. I think the stock motors run like 9.3:1 CR. I think as long as you keep all the emissions crap hooked up you should be able to pass. You could replace the cat with a high flow one too but if it works now its not a big deal.

 

I think 10:1 compression will be too high to run on cast iron heads with pump gas. You will probably either have to drop the compression about 1/2 point, or switch over to aluminum heads. If you keep all of your smog devices, use a 50 state emission legal cam, and have a good cat, you should have no problem with smog.