NEW Transgo P/N SK-400 shift kit for the 1965-UP TH400
This kit corrects the common problems with these transmissions, passing gear too easy, soft shifts, premature clutch failure, and late shifts. Along with fixing these common problems, you'll also see an increase in the life of your transmission due to the reduced slippage. This is the most complete shift correction kit available and definitely the most reputable. This kit is extremely easy to install and can be done with the tranny in the vehicle.
The shift kit listed comes with complete instructions.