Magnum head swap compression increase

IIRC, 63 cc's is typical for the Magnum chambers and 72 cc as stated above is typical for the LA open chambers. With a 9 cc change you can expect around

• 0.75 CR increase with the Mr Gasket 1121G head gaskets at .028" thick.
  
• 0.5 CR increase with the Felpro 1008 head gasket at .039" thick
• 0.3 CR increase with the standard kit Felpro gaskets, PN 8553PT at .051" thick

These comparisons are to the original head gasket that reportedly was around .025" thick + or -.