who runs 13sec to 12.80 in the 1/4

Good advice above.

See the approx. ratios? With what gasket? Remember, you can order a comteic gasket @ 4.040 bore and .060 thick or use a mopar thin gasket @ .028 thick and whatever the bore size is it comes in.

@ (lets round it off.) a .030 thickness difference and possible deck differences. It could vary like by as much as;

10.61-1 to 9,85-1 on gaskets alone.
9.43 - 1 @ .020 w/piston being down the hole or even worse, if the block is 9.6 vs 9.58. Before you know it, your ratio is 9.0-1 with the pistons listed @ 9.8-1.