I came across this old thread. I thought I would post some pictures.
American Racing published this advertisement. I have only seen it in old magazines twice.
Apparently American Racing offered to versions of these wheels through Shelby American, Inc. as both styles were sold on new cars. Both styles were offered in ½” width increments between at least 15X6 and 15X8.5.
One was the “drag wheel” design and is so described in some old SAI parts lists. The “drag wheels” have “bolt through” style adapter mounting. Dragon Snakes used them. I have read of trouble with the “road race” version tearing up if used on drag racers. They say the bolts wallow out the magnesium on rear wheels.
Front side of Dragon Snake 15X6 front wheel.
Back side of Dragon Snake 15X6 front wheel.
The second version was the “road race” style with “bolt into spokes” adapters. Ken Miles is pictured racing (CSX2431 ???) at least once with this style wheel. (The adapters do not interfere with the standard “red” length drive pins. I have confirmed this myself on CSX2551.)
Front side of “road race” 15X8.5 wheel.
Back side of “road race” 15X8.5 wheel.
The adapters and bolts for both wheel styles appear to be exactly them same, only the “drag wheel” gets plated washers and acorn style lug nuts.