Did you know that Ford built three completely different 351 motors, awhile back? 351-Cleveland, 351, Windsor, and 351 Montreal? (or, "Modified???)
The Cleveland motor had canted valves, the 351 Windsor had "true wedge" heads, and the 351-M was a tall-block, destroked 400, with canted valves.
Ma Mopar built 2 different 426's; a wedge ("street" engine,) and the mighty HEMI...
And 2 different 383's; a short stroke, and a long-stroke version.