Ok guys I would like to know wat my compression would be on my motor 408 pistons are flatwith a -3cc valve relifs, I will be using the gm gasket dnt know how thick that is and with 61cc heads or 72cc heads keep in mind I will be spraying

 

Any help greatly appreciated and thanx in advance

 

61cc - 12.2:1
72cc - 10.7:1

Approx also depends on deck height.

 

Well the deck hasn't been touched and for future refrenses how thick are the gm gaskets???