That sounds like the exact scenario that my neighbor did with his grain truck.
He knew he blew a hose but "thought" that it should run back to the house. Well I got it running for him and low and behold steam and water out the zaust pipe. Pulled the plugs and rotated the motor to check compression and got showered with coolant out of one of the holes.
long story short. He warped and cracked both heads. Put two used heads on that check good for no cracks and she ran on down the road.
Even if the heads check (magnaflux) good for no cracks they will also have to be checked for warpage and possible resurface or scrap them if they don't check out. As stated before the top end got toasted.
The bottom of that motor just may still be fine.
If you have to go to a repair place in the dark, I hate to say this but you better take your own vascelene, when they spot those out of state plates.
Best of Luck
