This engine is a very mild build with iron heads in a 63 Plymouth street cruiser. The builder is not in P.A. I do not want to bash them til we see how they handle the situation. I will say my friend had issues from the beginning with this engine including a rear main that leaked badly. My friend spoke to them at the nats about the coolant issue before we pulled the heads again.We had them checked again and local shop says they are fine they pressure tested them twice magnafluxed etc. The engine builder did not seam like they were very open to making it right if it was the block. I hope they will. I feel bad as I suggested this builder to him, as they supposedly really know stroker Chrysler bigblocks.