To quench or no quench

We don't know of the OP's friend's X head are ported or not. So could be a lot of extra cost there and he has the CNC SM's. Put on a .075" thick head Cometic head gaskets (or mill the pistons and use a Felpro 1008) and static CR will be in the 9.9-10.0 range either way, with a good quench/squish gap either way. Slightly better SCR than a stock 340, FWIW.

DCR will be round 8 with the cam at and ICL of 106. Ought to be a piece of cake to tune to stay out of detonation with those closed chamber, AL heads. As stated, engine is for the street and will never be raced.

IMHO the right path is use the heads he has to not put much more $$ into it and stop the friend's head from hurting anymore LOL. Seems like a case of 'better is the enemy of good enough' for a simple street engine that will be lots so fun to drive as it sets right now.