k i have an 03 gt so thats the l36 right? would it be any difference if i put the l67 heads in? and i know it would be better if i ported them but would i need any supportin mods for that to happen and how much would it be to port heads that are done right?

Why would you want to put in L67 heads? You would need to plug the injector bosses in the heads since that's where they are in the L67.

Porting is expensive unless you do it yourself and I wouldn't touch the heads unless you really knew what you were doing as you could do more harm than good.

Chico does porting for cheap, not sure about l36 heads but he is the man to talk to if you are looking to get this done.

isn't it the heads that are different between the two engines? so switching to L67 heads would actually be a performance decrease since you're losing compression?

I thought it was the piston's that gave it higher compression, I'm not sure though. That is why topswap people who even change heads over still have the higher compression and need bigger pulley's.

Pistons are taller in the L36, causing higher compression.

Don't bother switching to L67 heads unless you're going to add the L67 LIM and blower.

im just tryin to learn about what i can do without addin f/i but not a huge amount of $ but with decent gain

bang for buck is top swap. they are cheap now, like $400 or less.

Heads are easily $250+gaskets and won't net you the gains of a top swap. Rockers $200 ~10whp gain in high rpms under N/A.

Without going FI you are just wasting money. Anything that will net you a decent gain is going to be pricey.

There is a reason why people go with FI: it works.

Here is something to think about.

A GT3 cammed, ported heads, full exhaust with headers, Northstar TB, HV inserted GT put down 200 whp on a dyno. Those mods would probably cost you around $2000 give or take after all is said and done with gaskets and whatnot.

A topswapped GT will put down 200 whp for $400 + about $100-150 in gaskets.

now correct me if im wrong but wouldnt i have to get the fuel rails and heads and few other things from an l67?

yes but you can get a whole swap from someone for cheap. Topswaps are FS on CGP right now.