I bought a set of iron Pro-Lightning Pro-Topline 180cc runner, 72cc, bare heads. I took them to a shop for cutting the three angles to the new valves, but while I was there I let them talk me into making an additional 70deg cut right above the bowl, as seen in the attached pics. They assured me this would greatly improve breathing. The original three angles cut by pro on the heads are intact. They just added the additional cut.

Now I'm thinking why was I so stupid and not check with you guys first. Check out the attached pics. Can anybody tell me if this will affect performance? Or is it really a good thing?

Thanks.

 

that's fine, you're going from a 3 angle valve job to a 4... some people do 5.
now you can whip out your die grinder/dremel, and blend the bowl into that, for even better low lift flow!

 

A 75 deg would of been better.... The last set of ProTopline heads I did i used a 38 45 60 75 90... Pretty much the angles i use on most of the heads i do

 

Whew!

Thanks for your replies. I feel more relaxed now.