motor questions,

I was talkin to the previous owner of my honda, my grandma, and she happen to mention that the car had a new engine put in it when she got it some 14 yrs ago. Well i was poking the other day adjusting the valves i happen to look at ID stamp, it said BT. well "hmmm" i thought 'shouldnt that say A20?' So after some researching my 89 honda has an 86 engine or at least block???? :wtf: does that change anything parts wise? or same exact engine? Thanks guys

86-89 are basicly the same except the 89 had a little higher compression piston (9.3 verses 8.6) and the 89 had a better camshaft. The 89 had 120hp where the 86 had 110. Other than that they are all the same and the parts from 86-89 are interchangable.