Five new 1-inch crank mandrels for Chevrolet, Ford, Mopar from GZ Motorsports have 1/8-inch key ways in order to be compatible with other manufacturers. All five new mandrels are designed to be attached to the balancer using the pulley mounting holes located on the balancer.
GZ Motorsports has designed a new mandrel for SBC (small-block Chev), BBC (big-block Chev), SBF (small-block Ford), BBF (big block Ford) and SBM&BBM (Mopar) engines. The new mandrel has a 1-inch shaft with a 1/8-inch key way in order to be compatible with other manufacturers. All five new mandrels are designed to be attached to the balancer using the pulley mounting holes located on the balancer. This allows the crank bolt and washer to remain in place as required by several after market balancer manufactures. All mandrels come with a 4” long spacer so that each mandrel pulley can be accurately located on the mandrel by cutting each to length and an end-cap and bolt. The mandrels can be shortened as desired as the threaded 7/16 center hole is 2” deep. Each mandrel is of length to allow a mandrel pulley to be at a maximum distance of 4.5” from the back side mounting face, or face of balancer.
GZ Motorsports offers several 1” mandrel pulleys: 3”, 3.5” and 4.5” V belt and a 36 tooth Gilmer belt.
CM200A: (Pictured at top of page) The SBC mandrel uses flat-head countersunk allen-head screws to both hold the mandrel in place as well as center it on the balancer so that a crank trigger may be installed under it. The 7/16” threaded hole may be drilled to 7/16” to allow installation of an extra long crank bolt if desired, GZ Motorsports can do this upon request.
CM201A BBC side
CM201A: (pictured above) The BBC Mandrel uses the three bolt holes to mount the mandrel and a register to center it in the mandrel in the recess in the balancer. A crank trigger may be installed on the front of the mandrel or on the balancer with the mandrel installed over it. The mandrel may be drilled to ½” for use with a long crank bolt if desired, GZ Motorsports can do this upon request.
CM 202A: The SBF Mandrel uses either the 4-bolt ford pattern or the 3-bolt Ford pattern to mount the mandrel to the balancer and register to center the mandrel in the recess in the balancer. A crank trigger may be installed under or on the front face of the mandrel.
CM203A: The BBF Mandrel uses either the 4-bolt ford or 3-bolt Chevy pattern to mount the mandrel and the back is recessed to accept the BBF hub on the balancer, which centers the mandrel. A crank trigger with a 3-bolt Chevy pattern may be mounted to the balancer or to the face of the mandrel.
CM204A: The BBM/SBM Mandrel uses the 6-bolt pattern and uses flat-head countersunk allen-head bolts. A 3-bolt Chevy-bolt-pattern crank trigger may be bolted to the front face of the mandrel.