I use + for above deck and - for below deck on the deck of the pistons. The pistons do have a small dome as this is a bracket motor, I used the measurement directly above the wrist pins, rocking them forward and back and then average the results for the blueprint sheet, IE -.010 low and .001 for the high for both front and back rocking = .0045 deck hieght These pistons are the loose alloys and ended up with .007 or slightly more piston to wall clearances, so it has .0035 minimum per side, maybe a little more when rocked over and back . I may end up taking those heads off of that motor and put a set of 440-1 that Jeff CNC ported for me, got them back last Friday Thanks for banging them out Jeff Those heads should be at least 60 CFM better and there 8 CC smaller combustion chamber than the Eddy RPM heads on the motor now The 440-1 also have a set of Jesel paired shaft rockers on them so that should raised peak HP rpm some as well as make a little more power out of this rascal I will diffentitly(SP?) try remeasuring the total piston rock deck hieghts from the cam side to the block side instead of just front to back like I did on this the first time I called Diamond pistons after posting this and they said I should have plenty of piston to head clearances time for dinner, got to go for now