I just bought an L98 that came out of a 91 GTA. The guy I bought it from had alot of head work done to the motor including, porting the hell out of the heads, and adding roller rockers with dual springs. The motor has a Comp 306 cam in it. 112 LSA, 229/245. I've heard that this cam can be a bit much for a 350, so I want to go with a 383. Anyone have any recommendations? Should I go with flat top pistons, inverted dome? I'm trying not to spend a ton of money on the rotating assm. The top of the motor has about 5K on it, and the bottom has about 120K. So, I might as well replace the bottom end.
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Also, I plan on using the stock throttle body and TPI intake out of my 87 Trans Am. I'll probably port the upper plenum the best I can to get a little more flow out of it.

 

The problem isn't "350 cubic inches", it's "stock TPI".

I'd also classify this, "porting the hell out of the heads", as a "worry item".

 

The heads were ported, and milled 0.080. The spring seats were also cut to fit larger/dual springs, and Manley valves were installed in addition to the roller rockers.
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Could you "splain" please about your last reply, five7kid?

 

Hogging out iron from the ports is just as likely to hurt flow and performance as it is to improve it. Basic clean-up and smoothing is more effective than taking out a lot of material.

 

Im unsure as to how much porting was done. The porting work looks very good on the heads.