Yeah that's my fault it's 319. I changed my post, don't want any misinformation. As for the issues guys were having with putting boost to these cylinder heads, there have been several on other forums that have had heads permanently deform under boost and not seal right. They would pull the heads, get them nice and flat again, run them for a short period of time, and have the same issue. It was a vicious cycle and some guys even went to.....(fighting vomit).......an LS