The word was that all the brands of Hemi stuff were different. Very few would swap between the different brands, they would go with one brand and pretty well stick with that one brand.

Were I making motor mounts, I would expect to be building different brackets at the motor, or the frame, or both, for each brand. If they happened to be close enough to interchange, I would celebrate for a few seconds then move to the next part of the project. I've worked with 50s Mopar stuff for years, I don't believe there is such a thing as a definitive answer, lots of stuff was changing at the various Mopar camps during the 50s. By the early 60s, there was more of a shared mindset at Mopar. Gene