1992 C1500 auto 305 tbi 5.0L

I'm taking the top end apart to (if tests prove) replace #5 and 6 valve systems. Many questions here, please give any input on any of these Qs if you so please :P

Found lots of information on small modding etc etc on zhee interwebz... without putting my tranny etc in too much danger, to get some extra HP and/or fuel efficiency.

I DO have to replace most of the exhaust (pretty rusted out), so any suggestions on killer exhaust setups?

Milling the stock 305 heads from (I think it's) 58cc to something like 55cc for more compression? does that mean grinding down the head bolts?

Additionally, I found some used 462 camel hump heads, and 202 camel hump heads 64cc (lower compression?) with larger valve ports. both for pretty cheap. Could mill those bad-boys down?

Intake manifold spacer or TB spacer (heard this is little to no difference)

Additional cold-air intake (K&N?)

If I can find larger used exhaust manifold (idk what size mine is yet tho) for less back pressure.

Any knowledge and input super appreciated, of course :P

 

Well skip the exhaust manifold thing, go right to headers if possible. I don't know anything about those heads, but I'd call up an engine builder and ask about them. I've seen that people like to put on vortec heads, but I don't know anything about the ones that you're talking about.

I's say have the heads rebuilt and ported and cam it.