Vaccu Melt 300 1.76 Powerglide Carrier w/ Turbo Hydromatic Converter Splines.

TCI Hardened Input Shafts are constructed from hardened, aircraft quality Vaccu Melt 300 billet steel or Vasco 300 high strength steel. They feature increased lubrication flow and strength with a resized diameter that provides optimum stress distribution along the entire length of shaft along the extended high gear splines to the oil ring. See the chart below to compare TCI Input Shaft materials compared to stock and other aftermarket brands.