The Ford C-4 has been a very durable automatic transmission throughout its production life. It is coveted for its light weight and simplicity of design.
C-4 Transmissions made from 1964-69 are slighty different from the 1970 models. They had a smaller spline input shaft, .788" 24 count spline on both ends, compared to the later .839" 26/26 count shaft.
In 1971, Ford changed the shaft again, this time to a 26 spline converter end and 24 spline Forward Drum end with a .839" diameter. Our Fully Hardened Input Shaft is of the 24/26 spline variety.