Looking at the design of the C377, it seems like it should have been more
of a winner. Why did it flop?

My old CFI said guys would forget to start the back engine or not notice
that it would quit and end up crashing, true or not I don't know but it was
his story. I always thought it was an odd looking piece.

To that I would add that I personally think the 200 hp O-360's are not
enough power for the size and weight of the aircraft.