rocker shaft shims???

it was just .015" off what was there. Here is my big problem. I ordered pistons from mancini that have a compression height of 1.720".. the factory pistons were 1.760. I have no idea why anyone would make that low of a compression piston for a rebuild kit when the factory never even used that low compression piston in the first place. So I am trying to get my compression up to the 9.0:1 range but I keep shooting myself in the foot here. I had him take .015 off the block and now I am thinking of having him take .035" off the heads for a grand total of .050" off which will probably only get me back to where I was from the start if I use the felpro gaskets I have. I should have just got KB167's dang it!!!