I found a deal on a set of aftermarket wheels. They are advertised as front-wheel drive. Can these be used on a 71 Cutlass Supreme>

 

No, for two reasons. All FWD wheels have different offset than RWD cars. They won't clear the brakes. The other problem is that I'm not aware of a current FWD car that uses the 5 x 4.75" bolt circle of your Cutlass.