We have two 73 Mustangs. A street/strip built Mach 1 with a transplanted 351W (not C) that puts out a modest 360 HP, backed by a 4 speed AOD, and a 3.5:12 TractionLok rear axle gear set. Very spirited vehicle. The other Mustang is a Convertible with a totally stock 302 2v wihth a C4 auto tranny and a very steep 2.79:1 rear axle. Clearly the Mach 1 has far stronger performance than the vert. But as much as I enjoy the Mach 1 with its more than needede amount of power, the vert is the once I enjoy driving the most - hands down.
All I can say is it is better to find any rusted area before buying then after. Go ahead, ask how I know this. heh heh... No Regrets, but lots of experience along with plenty of cuts and bruises...