Only comes in a 20" shaft size
89 minmal octane f150 use less octane
sho 150 has a bigger altenator 50 amp
You can go t the yamaha website and look at the soecs and compare both motors to each other.
I think the SHO is directed towards Bass fishing boats, not a 21' bay boat
I got the F150 last week, its on my 21' Mako. I like it, pushes my Mako well!