[kstylianos]

If in fact your current deck heights are .50 and .75 with the .25mm shim, you will need to stack a combination of .25 and .50 shims but a deck height of 1.25mm is better as the chance of detonation decreases with a smaller deck height. You can also go smaller, not decreasing a deck height of 1mm if your piston to valve clearance allows. Unfortunately, you won't be able to check this until the cams are timed, but 1.25 should be safe for a stock build.

Some things to look at:

1) Are you sure the cylinder bases and/or case was not trimmed?

2) Make sure the cylinder is seated all the way down in the case bore.

3) Make sure to check the deck height on the wrist pin axis as the piston does 'rock' a little in the bore

4) Make sure the tip of the instrument is physically able to sit on the piston ridge. I used a gauge whose end was a bit thicker than the piston ridge and the slider would become lodged between the piston crown and the cylinder wall, not sitting totally flush on the piston ridge. I eventually used a gauge that had a skinnier slide.