A quick online search came up with
Quote
Chrysler: 2-13/16"
Ford: 2-3/4" (for the ones with a center hole that almost fits on a Chrysler, but not quite)

For the folks who are fond of the French units, that translates to:

Chrysler: 71.4375 mm
Ford: 69.85 mm

Kayse can't keep up at all now. lol