.06 and .10 or .006 and.010?

Valve clearances should be .010/.010 or .010/.012 I/E.

.006 is too tight. It might affect compression. Especially if the timing was not quite right.

So, while what you are describing really is starting to point towards the block, I would still give it another try. Worst case, the block is the problem and you have to get rid of it. Unless you are willing to pull the block, you are not going to be able to fix it.

Good Luck,
Michael