update update
well I removed the 273 from the 65 barracuda engine bay today and put it on the engine stand.. I did a check on the head bolts over #8 cyl that popped.. did a retorque and the 4 bolts over that #8 cyl loosened up ..... one bolt as much as 1/8 turn. all four bolts loosened up...
so went to check the remaining and some of them had loosened up also. this is with arp bolts 100 # and retorqued . disgusting !!!