Re: What's the difference, Johnson/Evinrude
With Evinrude vs Johnson from the early '50s on up, you'll see today where many have been swapped with the same identical parts from the other when something went seriously wrong. On Ebay for example, it's not rare to see 50s Johnsons with blue Evinrude powerheads or lower unit sections and vise-versa. I also have sevice/parts manuals....the same stuff. I've met guys who worked at OMC (Waukegan, Il) back in the '70s and said that they're the same.
So, it's then really a question as to which you can now buy cheaper if buying used or which looks best to you, best on your boat.
My collection of '50s Johnsons exists basically because each looks very unique to me. I'd have certain '50s Evinrudes too if the price was right and if I was still collecting but the nicer Evinrudes from that era are seemingly less common and sometimes costlier too.
Being a car guy who likes older GMs (some pre-78 but mostly pre-73), although they always shared many parts, the GM lines differed mechanically in their engines slightly as mentioned above until the '78 model year (possibly some '77s?). That's when a Pontiac could have a Pontiac, Chevy or Olds engine and that upset many in those days as GM didn't tell their customers that up-front at first. Even Cadillac used Chevy engines then.
Although Caddy, Olds and Buick were suppose to be a step up from Pontiac, then Chevy, the real differences were cosmetic only as none were mechanically superior to another. By the mid-eighties, all GMs were mechanically identical, just look different.