Valley pan sealant or no sealant

I've always sealed up the valley pans on the engines I've built but never built a high horsepower forced induction engine. So I had a engine builder build one for me. It's a 507 with a F2 Procharger. Had problems with it and it went lean. Was still going through the break in period so I wasn't on it had at all. Half throttle at the most. Got it home pulled plugs and popped the top of the ring landing off #1 #5 #8 and the valley pan was bulged up. Took the intake off and that's when I noticed there wasn't any sealant. What your opinion. He said it doesn't need it. I'm finding that hard to believe being forced Induction. Not saying that it was the cause of it blowing up but still trying to pin point the cause! Found the builders build sheet on ring gap. Top ring is .024 and 2nd ring is .015. Seems a little tight.