Hey,
Congrats I've always liked the 84 1/2's I've never owned one but A couple of my friends owned them,I drove them all of the time. As far as the rims go The TRX (Metric) ones were on most of them but there was also another type of mag wheel that could be had on these,I can't really describe them though? That said I just happened to stumble on somebody selling a good clean set of Original TRX Mag's that came off of a 79 pace car. I think he was only asking $150. If you'd like the contact info let me know? Good luck with the new purchase,My vote is too keep it stock(sort of,exhaust won't hurt it).Unmolested 5.0's are pretty rare these days not too mention a stock true 84 1/2 .