Since you did the resurfacing and new gaskets, and it didn't solve the problem, I'd definately recommend having both heads checked for cracks. It could also be cracked in the intake or exhaust ports (especially if a porting job was done), so make sure they check there as well. Nice ride by the way. I hope I've helped, and feel free to contact me if they don't find any cracks, so we can persue other possibilities. Good Luck.