The body changes ladeadhead mentions occurred a few years into the model run. Up until 1988, the cars look virtually identical from the outside except for the wheels (all 760s had 15", 740 had 14" or 15" on the turbos) and grills/trim (740s turbos got an all-black trim style with 'eggcarte' grill instead of the abundant chrome on the rest of the 7-series). From 1988 on, the 760 was redesigned inside and out, most notable visually with a new face and a new dash. Yes, the interiors of 760s had more luxury-type options. All 740s eventually got 15" wheels too.

The 760s had a "self-leveling" Nivomat rear suspension which the 740s did not.

Under the hood, 740s had either a non-turbo I4, a turbo I4, or a turbo diesel I6. 760s had a V6, a turbo I4, or a turbo diesel I6. On this board, the turbo I4 engine is generally regarded as the most desirable.

for complete model year-by-year info, you can go to any number of sites, but to get it from the horse's mouth, go to Ford/Volvo's official owners' site. It lists every feature of every model. You only need a valid Volvo VIN to register.

Also see the FAQ.