My 86 was the same setup a Tempest 300/Alpha, they have a higher X than the other 22's of the era! IMO better handling and ride than a BB I have very mild but over built 383 It makes a modest 370+hp, on a good day it can do 65.5, my cruise is 43 @ 5k. I went for tractable power not speed, I can get 4.3mpg if I am easy on it. What ever you do keep the Alpha, even doing it cheap it will coast a bunch to go to a Bravo. Yes more reliability but at what cost? You will be 2-3mph slower, relates to more fuel consumption. I made the mistake of getting caught up in the BS, I have a Bravo Diesel X on mine. Almost 6k just to get the squirt going not counting the engine and structural work! The 6k part of the deal would buy a lot of brandi new SEI Alpha drives with 3 year warrenties, or buy many seasons worth of fuel!
No matter what your beliefs are "GOD BLESS AMERICA"
Fully retired marine tech near 60 years in the biz.