1964 Chevrolet shortbed Stepside pickup - Done With Gears - Tech

Prior to installing the Gear Vendors Under/Overdrive unit in Jerry's '64, he was aware of the benefits he would reap with a taller top gear as far as engine noise and better gas mileage, but it was being able to select closer-ratio gears that really blew his mind.

Listening to Jerry's '64 Chevy as he sped away, the truck sounded like a dragster blasting through the gears at the dragstrip. This was due to the ultra-close gear ratios created by the Gear Vendors Under/Overdrive unit splitting the M-21 Muncie's stock ratios, plus its ability to withstand full-throttle power shifts. For example, the Muncie's 2.20 first gear becomes 1.71 with the Gear Vendors unit engaged, in comparison to shifting to the close-ratio Muncie second-gear ratio of 1.64 (which, thanks to Gear Vendors, no longer seems as close as it once was). For the next shift, since second-gear overdrive and third-gear direct both have a 1.28 ratio, the hot setup is to manually shift into third gear direct and then punch the Gear Vendors button for a clutchless shift to third overdrive, which is 1.00, the same as the Muncie's fourth gear. And now, of course, since we are back into fourth gear, where the final drive on Jerry's '64 is 4.10:1, his little 327 is turning some major rpm at highway speeds. This is where the Gear Vendors unit, with its 28.6 percent faster overdrive cruising, really comes into play. The 4.10:1 differential in Jerry's '64 in essence becomes a rearend packing 3.20:1 gears.

In comparison to a major manufacturer's mass-produced transmission manufactured with larger allowable tolerances and corners cut to save costs, the Gear Vendors Under/Overdrive unit is a precision-made jewel. Starting with the overdrive's cases sourced from foundries in Germany, England, and California, Gear Vendors custom-machines their internal parts in-house at their El Cajon, California, manufacturing plant. Gear Vendors precision-cuts their splines instead of rolling them. In conjunction with Gear Vendors' improved design of the legendary Laycock de Normanville's planetary gear arrangement and specially formulated friction materials from Raybestos, the Gear Vendors Under/Overdrive unit is capable of handling 1,200-plus horsepower. So it doesn't matter if you use a Gear Vendors Under/Overdrive unit for racing or just beat it as hard as you can on the street, they are unconditionally guaranteed for two years and are designed to last a lifetime.

Installing the Gear Vendors Under/Overdrive unit onto the M-21 Muncie is pretty straightforward and doesn't require any special skills. Since there are only four bolts that hold a Muncie in place, it was easiest to remove it and install the Gear Vendors unit on the workbench.

Thanks to keeping the 327 within its power curve, the '64 accelerated faster and was more tractable on the freeway, switching out of overdrive to function as a passing gear, then back to overdrive for better gas mileage.