Deck height

you need the CC of the cylinder hear
bore and compressed thickness of the head gasket (Felpro is .037 thick for both 3.4 and 3.510 bore gaskets)(stock steel "shim" gasket is .021 thick for both 3.4 and 3.510 bore)
Cylinder bore
Piston to deck height: you can do the stop method but its alot of work... just use a dial indicator and turn it till it stops coming up and measure it...

then use this calculator
http://www.wallaceracing.com/cr_test2.php