Because the C6 is a rugged transmission from the factory, very little needs to be done to make it stronger. For street and occasional strip, all the C6 needs is the larger intermediate servo and band.

Ford C6 Transmission Upgrades - Built Tough. CK Transmissions upgrades a C6 three-speed with modern amenities. HOT ROD Staff Writer Feb 07, 2012. See All 19 Photos.

From the November 1969 issue of HOT ROD: How to "trick-up" a Ford C-6 automatic transmission—make it live is the problem.