Had the same problem with E Street Heads and a Weiand dual plane on my 383/432 Stroker
Block was not cut , just cleaned up resurface - Made it clear to the machine shop
Used these gaskets on the head side of the valley pan , dry silicone bead side to the heads and ports then Edelbrock Gasgacinch to glue the gaskets to the bottom of tin pan itself
http://www.hughesengines.com/Index/...EJsb2NrIChMb3cgRGVjayk=&partid=33979Intake manifold side of tin valley pan no gaskets
Has worked awesome so far this summer
My latest set of NGK 6 look great with no oil use
Makes you wonder how much of that oil if any works it’s way through the exhaust system ? Was going thru about a quart every 500 miles or so for a few summers