i am going to rebuild the top end of my 91 RS 305 engine and i was wondering if i should just machine the stock heads and get new springs,valves,retainers,seals or should i just guy a set of the GMPP vortec cast heads that they sell in jegs for like $500 which would be better?

also i have TBI and i was wondering is the GMPP TBI manifold would be a good up grade for my engine?

also how big of a cam can you go with on a 305 TBI engine and will i need tuning?

 

The stock heads aren't worth doing anything to - other than throwing away.

Whether the Vortec heads are the correct replacement - that's a matter of opinion (not necessarily mine), but most anything other than '70's smog heads will be better than your stock heads.

Check out the TBI forum for your tuning questions (which you'll probably need).

I hope you have exhaust upgrades planned as well.

 

Take a few minutes and read this. This should really clear things up for you.

https://www.thirdgen.org/techbb2/sho...hreadid=227281