VaporTrail

I'm building a 84.5mm GSR block low compression for turbo. I have already replaced the manifold on the GSR head to Skunk2. Do you think I will need any head work (besides modifying the combustion chambers) to effectively have great power at 15psi? I'm thinking that the port/valve size might hinder me at top end. Educated thoughts and opinions are appreciated.

FAST94GSR

I don't think you're gonna get phenomenal gains so I wouldn't waste my money. Unless you're a racer and looking for every edge a stock head should flow just fine. Maybe you want to upgrade to larger valves or go with stainless steel valves but that is dependent upon your how much is in your wallet and if you feel like spending it.

b18bturbo

i would just add some retainers and valve springs nothing more than that.

rtype11

The most noticed gains you will find from port work is a simple port matching of the intake manifold to the intake ports. that will really increase flow and take out any obstacles. If you got cash of course do an angles valve job and full port and polish with lightweight retainers, springs etc.....

bigTom

i disagree... a head that is ported right will show significant gains... once again i say PORTED RIGHT! not no hack job which many people do... but if ur not going any further than little bolts on and a little motor work... then its not worth it... it kinda like the last step to ur motor imo... the head and the intake mani... those are the last 2 things imo