Yeah Bill, as far as I can remember Mike's old Sporty exhausts were OEM Harley-issue and were the same diameter and just slipped right on without needing reducers or increasers.
However, for further details I'd say maybe PM Mike and ask him about 'em directly, as I can't quite remember where and how the rear bolting points on 'em were attached to the bike.
(but like I said, they sure sounded great!!!)
