Used 1.250" billet set back blower plate. Racer made this plate from a 2.250" thick piece of billet alum. and designed it to set a Fowler or DMPE 6-71 thru 18-71 roots supercharger back 4.00" on part #1100-0015 blower manifold.
Set back is O-ringed on the blower sealing surface and attaches to the blower manifold with four 7/16" bolts. Front of set back plate has been contoured so the air from the blower will flow up to the front cylinders to help with fuel distribution.
Spacer weights seventeen pounds as seen in the pictures. If wanting to see if another supercharger will work with this spacer you will have to measure from the center of the second set of bolt holes on the blower to the front edge of the opening. This set back measures 3.750" to the edge, 3.875" to the center of the O-ring groove and 4.625" out to the front edge.
Customer has made big power on some BBC engines and says this spacer with the Indy intake worked very well picking up horsepower and balancing the nozzle jets in the ports. Picture three and eight show what the plate looks like mounted on the blower manifold. Buyer will have to re-drill there Indy intake bolt pattern to get the full set back of four inches.