Mmmmmm..... I see the error that leads to .009"....the original head gasket thickness is missing.
You subtract the difference in the gasket thickness from the .045" to get the changes. With the original shim at .025" (per my '65 FSM), and knowing that those Felpros are not consistent at .054" compressed thickness, but average around .050", that is a .025" gasket thickness change and a total change of .020". With those particular head gasket variations, then it can be .016-.024" change.....
Not to mention factory deck height variations, valve work, past work, tolerances on the pushrod lengths, rockers, cam and cam position..... there are a LOT of moving parts that can cause this to vary. The original lifter piston float tolerance was +/-.060" for a reason.
