I had a 73 chev pu w/ a 350 get a hydrolock, but not in a usual way. This occured because of a hole in the fuel pump diaphram. Several cylinders filled with gas. Not knowing this I just got in to go someplace and tried to start it....... nothing happened. The engine didn't turn over I could hear the solenoid kick in on the starter, then nothing. Finally after checking everything I could think of, I found what happened, pulled the spark plug siphened the gas out through the SP hole and turned the enging over by hand several times. Changed the fuel pump and the oil everything was fine after that. It was a bit scary for a while.....
AF