Fits Moroso Racing Vacuum Pumps or similar “smog” pumps that use OE-style, 3-bolt mounting pattern Precision machined from the highest grade aircraft aluminum and hard-coat anodized for extended service life Deep V-groove ensures belt retention under all racing conditions Machined with six holes to reduce weight 5" diameter pulley uses stock (3-bolt) mounting pattern with 1.16" bolt circle Use with Moroso Vacuum Pump Nos. 22640, 22641, 22642, 22644, 22840, 22842 and 22843