Oil Underneath Intake
I had a similar issue with oil in the valley. I had installed fabricated aluminum Valve covers on my IMM built 416 with Indy W2 heads. I tried a couple sets, each leaking oil in the valley area after making a pass. Finally found that the valve covers were 1/4” too wide for the head mating surface. Ended up purchasing a set of Holley Sniper covers, which were 1/4” narrower, solved the problem.
I had a similar issue with oil in the valley. I had installed fabricated aluminum Valve covers on my IMM built 416 with Indy W2 heads. I tried a couple sets, each leaking oil in the valley area after making a pass. Finally found that the valve covers were 1/4” too wide for the head mating surface. Ended up purchasing a set of Holley Sniper covers, which were 1/4” narrower, solved the problem.