Polished BDS Xcelerator carburetor adpt. spacer assm. This spacer is made from billet alum. to give a nice shine with no casting flaws that a cast part can have and includes cad plated grade eight mounting hardware. Top mounting surface is O-ringed and bottom surface seals with a screened gasket to keep harmful debris out of the supercharger. This spacer moves the carburetors up 2.00" and forward 2.50" and has six .375" mounting holes top and bottom. This spacer fits 6-71 thru 16-71's that use the 13.250" on center bolt pattern on the top of the supercharger and will work with most all 4150/4500 type carburetor adpapters.