I'd keep my Challenger ('70 Convert, Red/white top and interior) but upgrade:
Power - 340 in place of the 318
Transmission - 4 speed in place of the auto
Axle - 8 3/4 in place of the 7 1/4
Add the RH mirror
Maybe add rallye gages.

Dad bought it new and anticipated mom driving it, so some corners were cut. His first one was a purple big block car he had for a week. He really wanted red but the only red one on the lot was for the dealership owner's wife. The salesman made a deal to get it for him and the swap was made.