small block 671 blower ?

I have an Offenhauser blower manifold that apparently was done by Offy in 1990. It takes an Offy 4 brl manifold and converts it to a blower. Really nice job. Alkydigger currently has a new one on his site for sale. Wants a bunch of money. I'm currently building a 413ci smallblock with 6-71 and Hilborn bugcatcher. Hope to have it running before this season is over.