I thanks for your reply, motors been very hot it had 7 thou warp no cracks, I've had the head machined valves lapped, new head gasket new headbolts, rocker clearances set to 14 thou, very hard to start now runs very rough, lots of smoke, and seems to be pressurizing the oil, compression tested, and all cylinders well down best 150 psi, all others below 100 psi, don't see any other choice but to remove the head and remove the pistons? cheers paul