G-Force 30 Spline Mainshaft for LT1 & LS1 Camaro & Firebird T56 transmissions, also fits 04-06 LS1 & LS2 GTO. Made of 9310 Alloy, which is much stronger than your stock shaft. Designed for use with a triple cone blocker setup, will not replace the factory mainshaft in a LS1 Camaro or Firebird T56 without a complete 2.97 gearset swap. Please call our friendly staff for further information! #23 on the T56 Transmission Disassembled View, seen here, here and here.