The first thing you'll need to perform a T-5 conversion is a T-5. This gearbox is one that we had on hand and was completely rebuilt locally. You can find the upgraded Super Duty T-5 new at Ford Racing Performance Parts listed as PN M-7003-Z. The list price for the transmission is $1,469. Options abound for the T-5, from salvage-yard finds to custom-built boxes for road racing. If you're just looking for a nice cruising trans, as we were, a stock rebuilt late-model Mustang box is a good choice.