Sonnax Smart-Tech 10-clutch drum kit 28756-25K for GM Powerglides features a 35% larger piston that maximizes both engaging and holding capacity of the 10-clutch system. Smart-Tech components give you the option to reduce line pressure for greater efficiency, or drop to seven frictions for less parasitic drag and improved heat dissipation while retaining 10-clutch capacity.
Sonnax 10-clutch drum kits are optimized for Powerglide performance applications. Using the patented Sonnax 10-clutch drum system, the drum and piston accept 10 .060" frictions and 10 .060" thick steels, increasing lockup surface to allow significantly more torque than modified OE drums. The Sonnax drum has material removed for the kit's bearing, allowing overall stack up to be .060" taller than an OE drum alone.
I've used several of the Powerglide 10-clutch drum kits in drag racing performance builds. The quality and reasonably priced product makes the choice to use over a stock or reconditioned drum a no-brainer.G. Carson