Still waiting for my custom 8" 8 rib pulley--5 months now, it is apparently "lost" or misplaced in shipping. I got impatient and ordered a 10 rib 7" vortech universal pulley, which seems to bolt up to an 917991 ATI Damper, nearly perfectly. It was a little tight,but once mounted it is fine, smooth, no wobble. I don't know if the B.C. is officially the same.
My goal will be to try to get it running on 8 ribs (10 ribs I am sure will run into my fans...) with a 3.12 supercharger pulley it'll run about 20psi at 6800rpm if the belt doesn't slip. This is about 2 psi more than I've ever seen at the same rpm, but what I had wasn't really able to be reproduced due to belt slip.