Picture this if you dare: A vintage big block Mopar B-Body in the slow lane on the Interstate that sounds like it’s wound way too tight while doing little more than the double nickel. Adding insult to injury is the space cadet in a Toyota Prius passing this mighty Mopar at 75mph while talking on a cell phone. It’s enough to make a grown man cry.

If this sounds like you and your car, then it’s time for you bolt on the one product that will enable you to live life in the fast lane where you belong. What you need is an overdrive. Sure, the A-833 four speed or 727 Torqueflite you’ve got backing up that street Hemi or 440 Six-Pack is plenty stout, but neither transmission was offered by Ma Mopar with an overdrive. And if you’re running any kind of a gear, the situation only gets worse.

Above left: Checking angle of transmission. Above center: Checking the distance from the back of bell housing to the driveshaft, which indicates the length of new, shorter driveshaft that will accommodate the extra length added by the gear splitter. Above right: Marking the arms of the Hurst shifter to ensure that they are reinstalled on the correct transmission shifter fork arms.

Above left: Unbolting the U-Joint Cap bolts. Above right: Removing the driveshaft

Like you, there was a time when I got really fed up with riding along in formation with eighteen wheelers. The thing is, I really like my A-833 four speed. It’s an extremely strong transmission, rowing the Hurst Competition Plus is great fun, and the trans had absolutely no problem handling the power from the 440 Six-Pack.

When we restored the A12 inspired Six-Pack Wagon, we made sure that everything in the driveline was Mopar. And while I really wanted an overdrive, I did not want to change the trans out for a late model Tremec five or six speed. The answer was simple; just add a Gear Vendors Under / Overdrive to the back of the transmission and pick up an instant 22-percent overdrive. Adding a Gear Vendors to the big Plymouth would provide us with the perfect final drive ratio so we could cruise the California freeways at the same speed the cars in the fast lane were running without feeling like we were beating the snot out of the 440.

Above left: Removing bolts from transmission mount. Above center: Using Gear Vendors templates to determine clearance in tunnel for gear splitter. Above right: Hurst shifter arms unbolted from transmission.

Above left: Removing the transmission cross- member bolts. Above right: Unbolting head pipes.

With the header flanges unbolted, removing the transmission crossmember is possible.

Among the advantages of a Gear Vendor is reduced engine rpm and increased fuel economy, while a side benefit is reduced pollution. Yeah, I know that many of you could care less about what’s coming of out your tail pipes, but it is nice to know that instead of being branded as part the problem you can look the green weenies in the eye and tell them that you and your ride are actually part of the solution! Wanna see their jaw drop? Just lay it on how your ’70 AAR ‘Cuda is really an environmentally respected member of society. And don’t miss the look on their face when they realize you that you are more knowledgeable about reducing emissions on vintage engines than they are.

Another great virtue of a Gear Vendors is that it is an extremely robust unit. It’s rated at 1200 horsepower and can be found in dragsters that run two speed Powerglides like Jim Luttrell’s, who holds the Super Eliminator Record at 204.80mph. Another excellent example is Edward Miller’s 1970 Plymouth Duster that ran 8.63 @ 155.97mph to win the Pro Street Naturally Aspirated Category in the 2013 Hot Rod Magazine Drag Week Competition. Not only did the Duster win its class in competition, but it also completed the grueling 1054 miles between racing events. These examples speak volumes about the durability of the Gear Vendors Under/ Overdrive.

Above left: Remove drain plug from transmission. Above center: Unbolting transmission from bellhousing. Above right: Draining transmission oil.

Above: Removing speedometer gear

Above: Separating the tailshaft from transmission.

The Gear Vendors is easy to install, and if you start in the morning, your favorite Mopar can be back on the road the same day. Follow along with us as we install a Gear Vendors unit in the 1968 Plymouth 440 Six-Pack Wagon. Once you experience the thrill of a Gear Vendors in your vintage muscle car, you’ll never be able to drive without one again.

Oh, and the brain dead driver in the Prius with the cell phone; the next time this mental midget tries to pass you, just push the button and engage the Gear Vendors. Now you can put the moves on ‘em, that’ll let them see and hear what a Mopar is capable of while you drive past like they’re chained to a telephone pole. Bet they didn’t see that coming.

Above left: A-833 transmission without tailshaft housing. Above center: A-833 4-speed transmission with new Gear Vendors tail housing loosely attached, and ready to be bolted up. Above right: Tightening the tail housing bolts.

Above left: Transmission tunnel needed to be slightly dimpled to accomodate the Gear Vendors unit. Above right: Transmission reinstalled in vehicle with new Gear Vendors tailshaft housing, prior to installation of Gear Vendors. The slight dimpling marks are visible above the flange.

Above left: Splined coupling that mates transmission output shaft to Gear Vendors input shaft. Above right: Gear Vendors unit prior to installation.

Top left: Installing nuts on Gear Vendors mounting bolts where it attaches to the new GV transmission tailshaft. Top right: Transmission and Gear Vendors unit reinstalled in vehicle. Bottom left: New GV speedometer drive is mounted on Gear Vendors unit. Bottom right: The GV speedometer drive mates the factory speedometer cable to Gear Vendors cable. This device also sends speed signal to GV in car computer.

Install the new shorter driveshaft.

Above left: The stock driveline prior to installing the Gear Vendors gear splitter, and the final installation [center]. Above right: The complete driveline installation completed.

Routing of Gear Vendors speedometer drive, along with wiring that connects to GV computer mounted inside vehicle.

Now we’re ready to take our 440 Six-Pack wagon out on the highway!

All images courtesy of Larry Weiner. “Life in The Fast Lane” was published in September, 2014 of Pentastar Power Magazine.