I have decided to go ahead and build a 472 inch motor with mine. Mine will be in a street car and around 10-10.5 compression. I already have the dick landy roller rockers and a set of roller lifters. I plan on getting a camshaft in the 575-600 lift range. With the compression in that area is there still a possible head problem? I looked at the idy website and you can buy a rotating assembly for $1950 from them.