switchin from 89b2200 to 91 b2600?

alright this is wut im going to do my 89 b2200 its old tired and really dont have much power (but u all know this) so my buddy has this 91 (i think) b2600 x cab he said i could strip before he recycles it said the motor ran real good blah blah blah so wut id like to know from y'all is wut would be a few good things to check out b4 i do the swap? i know ill need the brain but is there gonna be any hidden joys jump out at me when im knee deep into it? its my work truck and ill have to make it happen in a weekend.i dont want a novel on how to do it just some suggestions from peoples on wut to expect thats all anyshort cuts tips tricks etc etc. thanks