Sonnax 10-clutch pistons and drums should ONLY be used as matched parts. See instructions for details.
Sonnax 10-clutch piston 28765-05 is optimized for Powerglide performance applications and machined specifically for use with Sonnax 10-clutch drums 28756-01 and 28756-08. These drums feature a piston bore that is .060" deeper for greater piston travel than was available from 10-clutch drums 28755-01 and 28755-08 (discontinued).
Using the patented Sonnax 10-clutch drum system, the piston accepts 10 frictions and 10 steels, increasing lockup surface to allow significantly more torque than modified OE drums.