hm....valves...questions....

I am not familiar with the heads but a few thoughts. When ever you can use Chevy parts go for it they are always cheaper. 11/32 stems are a good size for most performance applications that I am familiar with. Last don’t get to caught up on bigger valves, that don’t mean they will flow more air. There is a ratio between port area and valve dia. and many more factors. I just finished reworking my AFR 185 heads that the previous owner put 2.05in and 1.6ex. It did not help it, I have a friend that has a flow bench and tried all kinds of stuff (bowl/valve job/back cut on valve) started with 155cfm at .6 lift ended up with 165cfm. Even with the valve all the way open like 1.0" lift the head only flowed 170cfm. The port was just not big enough or the 4" bore was to small and shrouded the valve too. Also note that AFR claims more air flow and also are a 185cc intake port not these they only came out to 175cc.

Scott

i have a set of thumper ported e7's with 1.94 and 1.6 valves

Thumper of Orange Park


this man is the go to guy for head porting. he has a very good write up of why bigger is not necessarily better. he is also very good at answering questions in a pretty timely manner and he is also a member of this site.