They use flanged nuts and have straight holes.
Here's a picture of a "motor wheel" on a GMC with lug nuts, it's 20" but same bolt pattern as this wheel I found.
http://rides.webshots.com/photo/2576314380080251109NYlUTn

If you have what appears to be the same 22.5" wheel I have but with chamfered lug holes I'm pretty sure someone modified it.
Or, 6 lug Bud wheels also have an 8.75" bolt circle, but noticilbly larger and chamfered lug holes and a larger 6.5" center hole.
..... did you need some 6 lug Budd wheels and went about it the hard way?. They' would be new Accuride part number 28157, page 17 as well as readily available (even in different widths) used in junk yards.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-