I'm going to send my head off in a couple of days and I was looking for advise on valve size.I have one cracked valve on the exhaust side and wasn't sure whether to replace all of them(with stainless) or just the one and get a 3 angle valve job,springs,retainers.If I did go with the stainless would it be better to get oversized or stock sized?I am also going to have my block sleeved to 84mm.Should I get the chamber on the head matched for the bore size?How would it effect compression?I know I wouldn't have to but what would the compression be either way?Any help would be appreciated.

BTW this will be for about 400-500hp.

 

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I'd replace all the valves, no sense taking a short cut. I'd go oversized stainless if you can afford it.

 

The valves are the same price oversized or stock size.Which one would be better?

 

I think Boosted-Hybrid and headgames confirmed that oversized valves arent really needed.
Just an FYI. I dont remember the specifics though.

 

Thanks for the info.

 

Yea, we made 670whp on Jeff Evans dyno..stock sleeved, stock valve size.