Goodwrench is right on this one. Had a 1971 Penn Yan that had a 350 GM motor in it. The owner before me, filled up one time with diesel fuel, and blew the motor. Whoever did the rebuild, didn't do a very good job, as I had it less than 2 years, and the motor went bad. When I went thru it, a friend of mine, who worked as a boat repair mechanic, said it was a counter clock wise rotating engine. The main shaft bearing seals had the wipers in the opposite direction, to keep the oil in the engine. If I had left the original ones on, in the motor I was putting in, the oil would have been pushed out of the engine, instead of pushed in. -gypsyman