So what can you do to a head?

[Lunner]

As the topic says really, what can you do to a head to get gains, and what sorta gains, and rough costs.

I know about porting and polishing it, and heard about bigger valves, but thats about it really.

Will be working on an 8v head btw

[clowo16v]

Duno about Renaults, but in general.

Porting & Polishing
Skimming (to raise CR)

As for valves you can usually get bigger ones in there, and usually a proper 3 angle valve job is done at the same time (cuts the valve seat at 3 angles, with the middle angle being where the valve head closes to)

There's also actual inlet/exhaust port reprofiling which is really only good on racecars, by using epoxy putty to build up areas and then port them out to a different shape from standard.

See ya

Matt