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Second Chance Garage

For the Classic Car
Restoration Enthusiast

Second Chance Garage

Second Chance Garage

For the Classic Car
Restoration Enthusiast

Second Chance Garage

Second Chance Garage

For the Classic Car Restoration Enthusiast

Second Chance Garage

RESTO-MODS

Resto-Mod Restorations — Part 15: Drive Train

Transmission swaps are common in Resto-Mods. Muncie four-speed gearboxes are a popular choice of builders who want to keep a Resto-Mod "all Chevy." Muncies can easily be adapted to a wide range of GM and non-GM cars.

Jeff Noll's Muncie M-21 close-ratio four-speed manual transmission is supported by a sturdy cross member at the rear of the tailshaft.

Jeff Noll's Muncie M-21 close-ratio four-speed manual transmission is supported by a sturdy cross member at the rear of the tailshaft.


There are three basic types of Muncies: M20, M21 and M22. Jeff Noll's '67 Camaro uses an M-21 close-ratio four-speed with a Hurst Competition Plus shifter. Jim Mokwa used a Tremec six-speed in his GTO. This is a very popular Resto-Mod transmission. Some builders prefer the convenience of an automatic.

Jim Mokwa's high-tech Tremec six-speed manual transmission looks small bolted up behind the big 400-cid Pontiac V-8.

Jim Mokwa's high-tech Tremec six-speed manual transmission looks small bolted up behind the big 400-cid Pontiac V-8.


Jeff Noll's Camaro has an 11-inch Centerforce diaphragm clutch. Jeff's third member is a 10-bolt Positraction rear end dressed up with a billet aluminum cover. Inside the axle you'll find a Motive Gear 3.73:1 ring and pinion gear set.

Jeff used a 10-bolt Positraction rear axle with a billet aluminum cover and a Motive Gear 3.73:1 ring and pinion gear set inside.

Jeff used a 10-bolt Positraction rear axle with a billet aluminum cover and a Motive Gear 3.73:1 ring and pinion gear set inside.


Muncie Four-Speeds

Muncies came in many GM models of the '60s and '70s. They were used in muscle cars and Corvettes. Milder GM cars had Saginaw or Borg-Warner four-speeds. A Muncie differs from a Saginaw in that its reverse lever is in the tail housing, not the side cover. One difference between a Muncie and a Borg-Warner is the Muncie has a 7-bolt side cover (two less than a Borg-Warner).

Muncie serial numbers have nine symbols that tell the GM division, year, model, assembly plant and car they were used in. The first symbol indicates division, the second matches the last digit of he model year and the third tells what assembly plant the car was built in. The last six match up with the car's VIN.

Hopefully Jeff checked the numbers on his Muncie before he started this install. Some models are more valuable to a purist than to a Resto-Mod project.

Hopefully Jeff checked the numbers on his Muncie before he started this install. Some models are more valuable to a purist than to a Resto-Mod project.


Before installing a Muncie four-speed in a Resto-Mod, check the serial number and other codes. You may have a tranny that is worth a lot of money to a purist. You could probably swap it for a better unit and get cash to boot. Finding the right box in a junkyard could even be turn out to be like winning the lottery.

David West of Milwaukee, Wisconsin, actually 'restores' Muncie transmissions and harvests the rarer cases for collectors.

David West of Milwaukee, Wisconsin, actually "restores" Muncie transmissions and harvests the rarer cases for collectors.


According to transmission guru David W. West of Davids 4 Speeds LLC, all Muncies work on the same basic principle. The input shaft goes to the cluster gear. The cluster is mated to all the speed gears, first, second third and fourth. The speed gears are independent of the main shaft. The magic is in the synchro assemblies. The synchro hub is splined on the main shaft. The slider and the synchro ring grabbing on the cone of the gear allows the slider to engage the engagement teeth. That's the shift process. Downshifts go into the next gear.



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