The problem is future maintenance as well as resell value. Once you start mixing and matching parts on a car things become a pain to maintain, especially if the person doesn't keep good records and/or if the original install is hacked. I've built and worked on hot rods for 50 years and the worst ones to work on are the ones where the guy did everything on a budget. Just worked on a '56 Ford F100 the other day with a Pacer front suspension. Someone thought that was a good thing to do 40 years ago but these days it seems kind of dumb. Just saw a Volare suspension cut out from under a '48 Merc pickup because it was a worthless pile of crap. Someone 30 years ago thought they would save some money by using a Volare suspension rather than buy a Jim Meyer kit. Now the job has to be done over because it was a stupid idea.

Personally I wouldn't use a 8.8 under a B body Mopar because it seems like a cheap solution. Cheap solutions cheapen the car. If it is just a RoadKill type of hack job then who cares. If the OP is trying to build a nice car then he should stick with a nice solution. There are lots on the market. Hacking a car together can be fun and a good experience, but in the end it is a waste of money. Of course, nobody wants to be told that, they would rather do it and find out the hard way. That is just how it works.