B body 8 3/4 in an A body

I'm going to check out what looks to be a 54 1/4" flange to flange B body rear this weekend. The seller told me it'll fit in a later model A body with stock wheels no problem. I'm wanting to put it in a 67 Barracuda. I believe I have a set of 14x6 wheels with 3" backspacing at home but I'll have to measure when I get there. I'll have to find out if the spring perches have been moved yet or not as well. Will this rear fit under my Barracuda without rubbing the quarters? Thanks.