After the first fire up I checked the timing and it was way off like the distributor moved alot . 13* initial , 14* mechanical, 27* total.. I strongly believe this why the head gaskets blew 2 times.
DETNONATION. never heard any signs of pinging even when lugging it in 3rd gear ... dist advance can hooked up . timing should have been run at 34* total ... 20* initial 14* mechanical.