7 1/4" Axle Education

Jim, I don't know the difference or if there is one, but here is what Summit shows for the 63. When I plug in 66, I get 3 more choices. I think they are the same, but I am not 100% certain.

1963 DODGE DART Ring and Pinion Gears - 7.250 in. Ring Gear Diameter (in)