Adapting the

Chevrolet & GM Standard Shift Bellhousings

to the

Jeep T98 Transmission

as found in

Kaiser M715 & M72x Military Trucks

Jeep Adapter kit to GM Bellhousings

Kit C715, adapting GM small & big block bellhousings to the M7xx T98 transmission

These terrific M715 & M725 "5/4-ton" trucks are great conversion candidates, and make even more excellent vehicles when converted to Small Block or even Big Block Chevy power.

These plate style adapters are machined from high-grade aluminum alloy, featuring thick flanges and a heavy cross-section.

The adapter installs onto these transmissions with no change of input gear or other transmission internals. Cutting the transmission input shaft is not required as the adapter spaces the transmission properly for the GM crank and clutch assembly. A new pilot bushing is required for this assembly. See Related Products below for the one matching your particular GM engine.


Included are the two adapter plates, GM bellhousing locator / throwout sleeve, and hardware.

Installation Requirements

The adapter is easily installed onto the T98 using normal mechanics tools. Instructions are included. Disassembly of the transmission is not required for the typical scope of this conversion.

Applications & Compatibility

Compatible Engines

Nearly all GM Generation I-III engines are compatible with this conversion, including Chevrolet Small Blocks, Gen III+ V8's, Chevrolet V6's and Chevrolet I6 engines. Also, Buick, Olds, Pontiac, and other GM engines are compatible with this adapter assembly if you have a standard shift classic GM bellhousing and flywheel for your engine. Even some of the front wheel drive and unique engines could be made to work with this adapter using certain factory or aftermarket bellhousings sharing this common bellhousing / transmission bolt pattern.

GM Bellhousings

Chevrolet Muncie Saginaw Bellhousings

The classic Chevrolet bellhousing, with the four-bolt rear pattern. Buick, Olds, Pontiac and other bellhousings with the same rear face are equally compatible.

Your GM bellhousings will typically feature either a 4-11/16" rear face bore or a 5-1/8" rear face bore, the latter typically only from Chevy / GM trucks from 1968-1991. Our adapter works natively with the smaller bore bellhousing and with the larger bore bellhousing if you choose the 5-1/8" press-on spacer ring. If you are unsure of your bellhousing bore, buy the ring and return it after your build if it turns out you don't require it. See Related Products, below.

Clutch Assembly

Because of the 1-1/8" x 10 spline configuration of these transmissions, use an off-the-shelf GM clutch kit (pressure plate & disc) with this conversion.

Be aware of the following clutch configurations - see Related Products below for more information:

  • 153 tooth classic flywheels typically use a 10-1/2" clutch assembly
  • 168 tooth classic flywheels typically use a 11" or 12" clutch assembly
  • Gen III+ engines should use a taller aftermarket flywheel that normalizes the clutch kit to a classic 168 tooth style

The pilot bushing included with most clutch kits will not be compatible with the pilot tip diameter of these transmissions. See Related Products below to select your proper pilot bushing.

Clutch Release

The factory style bellcrank linkage system can be retained if the installer uses a GM release arm, #RAGM. This release arm is the best choice of release arm for either a GM engine swap in 1972-1986 CJ models, and some FSJ Jeeps - with the factory mechanical release system (not hydraulic). It's proper length gives the correct release action for GM clutches and is compatible with later rod & bellcrank linkage systems found in these Jeeps. See Related Items, below.

Some installers use this as a time to upgrade the factory's direct bellcrank style linkage with hydraulic release. Master cylinders from later CJ's and YJ Wranglers (the 1987-1990 version being most popular) can be installed on earlier CJ firewalls, and your GM bellhousing will accept one of Novak's popular #HCR Series slave cylinder kits, which include the release arm. For these and the appropriate hydraulic clutch line, see Related Products, below.

Clutch release bearings need to be a GM compatible unit. Because of the various heights of pressure plate fingers, consider Novak's adjustable throwout bearing assembly, available in Related Products, below.

For more theory and in-depth discussion about clutch systems, see Novak's Guide to Clutches, Linkages and Bellhousings.

Compatible Transmissions

This kit is specifically for the M715 Borg-Warner T98.

Related Products

GM crank to Ford pilot bushing
Jeep T14 to GM pilot bushing
Jeep to GM Clutch Release Arm
Adjustable clutch release throwout bearing
Hydraulic release master kit for Jeeps
Hydraulic release master kit for Jeeps
Adjustable clutch arm pivot
GM LS Vortec Bellhousing
GM Chevy Bellhousing
Extended depth flywheel for GM engines
Bolts for GM engine flywheel to crank
GM clutch kit
GM clutch kit
GM clutch kit
T18 Parts

Engine Placement

Classic Chevy Small block installation into the M7x5 will require minor firewall modifications to clear their rear distributors, if leaving the transmission in the factory location, which we generally recommend.

However, GM Gen III+ engines (distributorless) do not require this and are recommended over the classic Chevy engines for this and other reasons.

Since engine fore-aft and left-right offset location is dictated by the transmission location, the installer should be careful to install the engine at the same height and crank centerline at about the same location as the outgoing factory engine.


Driveshaft and jackshaft length changes are not required nor recommended for this conversion.


Use of the uncommonly strong factory axles in these M7x5 trucks is completely acceptable with this conversion. Axle upgrades are not necessary, but they may be chosen for reasons external to this transmission upgrade. However, gearing changes for better road gearing may be considered.

Also See