I know, that's a broad question and you have to include a lot of other information, needs, wants with it so sorry if I upset anyone.
In my situation I'm probably going to use my version 4 inlet manifold so I'd need to stick with ver 1 to 4 heads?
The reason I'm asking this is because someone is selling a pair of heads that have been ported but kept all the hardware standard but is making out that they are the greatest things since sliced bread.....(I might be slightly exaggerating here )
But, he says they are STi RA heads.
My understanding was the ver 3 & 4 STi heads were good to use but I didn't know if the RA heads were even better??

Also, what would you have done if you was building a new engine up? 1mm oversize valves? Uprate the cams but to what spec?
Was looking to build a 2.5 bottom end (because I have one) with 2.0 heads to put in my TypeR.
Not looking to set the world on fire, just looking for a strong quick engine.

Many thanks for taking the time to read and I look forward to your replies

 

STi & STi RA are basically the same spec for V3 & V4 cars (WRX RA is more std)

if they are genuine STi spec then they will have the small watch battery type shim sitting in the top of the valve locator under the bucket........

as for the rest would all depend on power target, etc.

 

He does state "Heads are shim under bucket with the lightweight shim style." so I assume that is correct with what you have said?
I have a set of ver 3 STi heads so would assume them to be the same?
Just don't know if it's worth the money for just the porting work he says has been done?

 

your heads are basically the same in the case...........

all depends on who has done the porting and how well they have been 'flowed' - its far more technical than simply cleaning up the ports as some seem to assume