I worked in a tire store in the early 70's The wheel you are refering to was an ET IV. The oval washers either had a center hole, which was used fro 4 3/4" bolt circle. Or a offset washer which could be flipped for either 4 1/2" or 5" bolt circle (big GM Pontiac, Olds, Buick). During this time I never saw any uni-lug wheels from Crager, ET, or Ansen (Sprint II) that fit the small 4" pattern. The 4" pattern was refered to as BVD ( Baracuda, Vailiant, Dart, Duster). ET IV and Ansen Sprit II were both polished slot mags. Ansen Sprint I was a brushed finish an straight lug slot mag. They were availbile in 14x6 ,7 ,8 ,10 in BVD. No 15" were available in BVD. I had them on my 68 GTS 383 convertible. 14x6 with E60x14 and 14x7 with G60 x14. Cragar Spokes were also avaiable in BVD pattern. As I remember that was about the only 2 wheels in BVD.
Doug