440 871 supercharger ?

Who's blower case is it? GMC never made an 8-71 blower...all those rotors come from 8V71's and the cases are all aftermarket.

Gary Dyer and his son are experts. I think Gary is retired. I sold those guys a half dozen 6-71 cases and rotors several years ago.

Another good shop is Dean's Blowers in WA. Rick Dean did the gas conversion on my 6-71 Hemi blower.