Stockish 340 upgrades, cam needed
Agreed, you have to be accurate to within a half cc per one tenth (0.1) of a point of compression by the “hand grenades and horseshoes on line calculator”. The criticality of how close the compression is between the 9.8:1 and 10.5:1 is going to be dependent on intake valve closing, altitude, and fuel octane rating.
So far I’ve refrained from mentioning the dreaded alternative fuel route. Some TRW domes milled for a final compression of 11-11.5:1 with some e85 on a “close enough tune” with the fuel available during the time of the year it’s going to going to be driven the most (bring it varies from 70-85 % from winter to summer blends!) would be the best route to take the atomic cylinder heads to some resemblance of true street ability. Big DCR with the somewhat short duration cam and it could probably be idled out from a stop.