GM Turbo Hydro 350 Fairbanks Superior Transmission Posi Shift 2 Stage Kit 1969-1979 This 2 Stage Shift Kit from Superior comes with two levels of performance: 1. Heavy Duty 2. Street & Strip This shift kit firms up 1-2 and 2-3 shifts, includes an oil transfer plate to give the best holding capacity in 3rd gear as possible, replaces worn out separator plate with the new special design plate, and improves overall performance. The Posi Shift 2 Stage Pac's are by far the easiest available way to step up transmission performance and can be installed with the transmission in or out of the vehicle.