Will fit Chevrolet 3 bolt pattern on 3.2″ bolt circle. Also fits Ford 3&4 bolt pattern on 3.3″ bolt circle. Please specify which bolt pattern required when ordering.

Manufactured from a combination of 7075-T6 and 6061-T6/651 aluminum our drive mandrel was designed to be rugged, reliable and versatile. Our drive mandrel is mounted directly to the face of the balancer (with or without a trigger wheel) eliminating the long bolt that retained both a mandrel and balancer to the crank shaft. Your balancer is now (reliably) retained by a separate bolt. The 1.250″ hex drive nut/pulley retainer, manufactured from 7075-T6 aluminum and hard anodized, is splined to the 7075-T6 aluminum mandrel shaft. With the positive engagement of a spline your engine can now be manually rotated in either direction, when valve or cam adjustments are required, without (inadvertently) loosening or over tightening the balancer retaining bolt.
Splined mandrels are not new, however they are often unique to each manufacturer requiring the use of ONLY that manufacturers “special” pulleys, spacers etc. The design of our spline allows the use of ANY pulley styles incorporating a 1.000″ bore with 0.125″ keyway. You won’t have to throw away your pulleys and spacers to upgrade to this mandrel.