Usually, one of the first hard parts to fail when the HP begins to climb is the input shaft.
Any C4-equipped car with heavy modification needs an input shaft constructed of superior metal with proper heat-treating.
Made to fit post-1970 C4's, Dynamic Racing Transmission's hardened shaft, especially when combined with our Solid-Strength Forward Drum, has proven itself countless times in street driven hot rods and competition vehicles as diverse as baja racers, and 1000+ HP Renegade Mustangs.
This is the same shaft that is used at DYNAMIC in all of our high performance C4's including the well known Mighty Mite lineup.
NOTE: When just changing the shaft, no disassembly of the transmission is necessary.