I had my 396 BB 390 heads reworked with big valves (2.19/1.88) My question is have any of you had any clearance problems and what route did you take if you did. Flycut the pistons? Replace the Pistons and with which ones? The cam that came out had a lift of about .400 before the big valves. I want something about .550 Would like to know your experiences. THX