>>>*The way we do it is TDC the engine, measure the distance down the bore of the flat part (outer ring) of the piston.

Zero is good, down the bore becomes bad for performance very quickly. .010" will run just fine, varations of more then a few thousandths begin to stack up effect.

We always must tune to the weakest cylinder of course.

We see a LOT of remanned engines with varations and once in awhile run into one that has wild variations of .030" and more.

The cause is always the same, regrinding a shaft without indexing, at .010" it isn't bad, at .020" it gets worse, and at .030" we can see big differences in deck hieght.

Then add in resizing the rods? Yes, big differences.

For an engine that just needs to run, not a real big problem. When you are looking for that extra 10-12 ponies, it matters...But of course to deck the block you need to take it back apart. If you do, the cut should be to zero for the piston that is highest up the bore....*EB