It's an interesting fact that although the original Mustangs were lightweight and sporty, an overwhelming majority of them came with an automatic transmission. Many buyers were young people on a budget or a family looking for a second car. They liked the automatic transmissions for a number of reasons. The C4 was a reliable and trouble-free gearbox, and there was no clutch to wear out and change. An automatic was great for everyday driving, especially in heavy traffic where a manual transmission could leave the left leg numb from working the clutch in a prolonged snarl.
Although never originally conceived as a high-performance car, it nevertheless delighted Ford fans everywhere when the Mustang turned out to be such a great performer. The new car wasn't a traditional musclecar and certainly not a drag racer. In 1965, everybody knew that a Mustang with a 289 would fare poorly against a GTO with a 389 in a stoplight showdown. No one can afford to give away 100 ci in a drag race. What people didn't realize back then was that with a few minor changes, a Mustang could run neck to neck with a Corvette on a road course and score repeated victories against the expensive and elaborate Stingray. That the economically built Mustang with parts borrowed from the pedestrian Falcon was a successful competitor against a purpose-designed and -built sports car came as a big surprise to many, including the folks at Chevrolet.
If your dream is to own a weekend road warrior straight from the Total Performance Years, then a classic Mustang is a great car to start with. Besides a healthy engine, the most important component for a successful road racer is a manual transmission. The freedom to select gears manually is of tremendous help for both entering and exiting corners.
Instead of a T-10 or a Top Loader, which are both excellent transmissions, we've decided to add freeway flying to our '68 Mustang's list of abilities and go with a T-5 overdrive conversion from Ron Morris Performance. RMP makes many of its own components for a variety of classic Ford applications and all of its offerings share a common denominator of quality and thoughtful engineering.
We want to update our '68 Mustang convertible with a 289 and a C4 to a T-5 five-speed transmission for more enjoyable cruising with less expense than a direct conversion kit. Let's look at the wide variety of components needed, and then we'll walk through an RMP installation on site at their spotless facility.
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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. | 
We'll need a manual-transmission bellhousing. Since a cable-style clutch-activation system is being used, the T-5 housing is the one we want. Those with a car having a stock manual-clutch linkage may decide to keep it and use the commonly available adapter plate that will mate the T-5 with the OE T-10 or Top Loader bellhousing. The FRPP part shown here is a late-model 5.0 bellhousing, PN M-6392-E. It costs $199. RMP also carries this bellhousing, if you're looking for one-stop shopping. Of course, if you're salvage-yard hunting for your T-5, you should be able to get the bellhousing with it, too. |