Your present c.r. is about 8.3:1 which will support something like the XE250H at most.

With all else being equal, a change to 64 cc heads will result in a static c.r. of 9.5:1 and you would be able to run either of the cams you have on hand. However..........

You will not be able to run 9.5 c.r. with iron heads on pump gas without minimizing the squish to around 0.035" to 0.040". That means a complete teardown and decking of the block. You may squeak by with aluminum heads without the teardown.

This is just my opinion based on 50 years of hot rodding, others may have a different opinion.