18" Wheel help

The wheels on the early A-Body look like American Muscle AMR's.

Here is an 18x8 w/ 5.7" BS

Mustang AMR Charcoal Wheel; 18x8 (05-09 Mustang) - Free Shipping

They also have 18x9 and 18x10, but you aren't going to get them to work with a stock width A-Body 8.75. I think you could step up to a '67 or so B-Body and make them work though.

Beside the issue Andy raised of the bore size, also be aware of the depth of the nose of the rotor. Most wheels are fairly short in that area and the wheel has to be bored out all the way which means the original center cap won't fit. Plus the bearing cap on the rotor usually sticks out of the wheel anyways.