318 heads

George Jets said
Most likely people ran them low on coolant and then got them hot.
(the ones that cracked)

The Reman 302 heads have buttons on the front frost plug as a temp sensor.

As long as you don't get them hot and the button drops off, they give you a full one year warranty on them if you don't over heat them.

I've found a number of exhaust seats cracked on "oldie-but-goodie" heads, frozen/not operating heat-riser flaps stuck partially to fully shut dumps all of the exhaust & heat through the 2 exh ports at the crossover ports...new crack city..