1" to 7/8" Clutch Slave Swap

A common practice on Superformance Cobras has been to use a 7/8" slave on Small Block cars with an OEM bellhousing and a 1" slave cylinder on engines with a blow proof bellhousing.  One issue this causes is that when combined with the Superformance factory supplied 7/8" master cylinder, the 1" slave has less stroke.  To remidy this some owners have opted for a larger 1" master cylinder.  This project achieves the same results by replacing the 1" slave cylinder with a 7/8" slave cylinder.

Original 1" slave


7/8" bore x 1.25" stroke slave. Part # 91025605 from speedwaymotors .com  The push rod and mounting block are custom fabricated.

The Speedway slave does not include a snap ring to prevent the piston from blowing out the end of the cylinder if it is not adjusted properly.  If you want the safety of a snap ring the same part is available from McLeod Racing, part # 139006, but the McLeod piece is more than twice the cost and the stroke is reduced to 1.1" to aqcomidate the snap ring.  The McLeod unit also includes a push rod, but it is not sutable for this particular instalation.

7/8" slave installed.  The two highest 1/2-13 bellhousing bolts shown in the original install photo now attach the 7/8" shave mounting block

After install, adjusting pedal to allow about 1-1/8" travel provided best action


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