Jegg's has Cometic in .027' and .030"
Cometic Gaskets C5633-027: Cylinder Head Gasket Chrysler 318/340/360 | JEGS
Cometic Small Block Mopar Cylinder Head Gaskets | JEGS
Most of the time just snug the nuts down with a 1/4" drive. I think that it is like 25 in. pounds. I looked in the service manual and there is no spec listed.
Do not over tighten the bolts
Good luck