A little O/T (my apologies), but part of the early speed gear. Looks like a J-75 Marshall-Nordex Roots-type cabin blower, also known as a Godfrey blower. These were used by Barry Ekins in the late 1960’s in Sydney as part of a kit for around 400 vehicles, including around 25 Holdens and 50 VWs. Also used in some historic racers, and in this case for a brick:
http://www.ebay.com.au/itm/Supercharger-cooper-s-mini-or-morris-/221693754615?#ht_280wt_1363The eBay username suggest someone with an FC-bent... one of the forum members?
Cheers,
Harv (appreciator of vintage superchargers)