I ran a drag motor all last year,4.155 bore,.007 cyl.clearance .005 out of the hole and .041 gasket .036 piston to head,shift at 76-7800.When I took it apart 4 pistons had been hitting the head,all on the right bank,the deck clearance on all cylinders were set the same when it was first built.The top ring grouve was still good so i took .003 off the pistons and now have .039.I won't have it apart till next winner to see if they still hit,unless there's a problem.Just saying .036 might be to close in my combo.Bill.