Rumor has it that somewhere, General Motors has a nutcase engineer that they keep stashed away in a rubber room. Every now and then, he escapes, and designs an engine, or an entire vehicle, and they capture him, sedate him, and lock him away again.
Some of his more noteworthy projects have been the Corvair, the Vega, the Pontiac OHC 6-cylinder, and of course, the Toro-Flow Diesel. It was intended to be a Diesel conversion of the GMC V-6 that would sharwe as many parts as possible with the gas engine. I think by the time it got off the drawing board, the only shared part was the oil pan. The diesel was an utter flop, and never was very successful.
So much for compatibility!
Jerry