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.
The first thing you'll need...
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...
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.