JBC 1947-53 Chevy Adjustable Transmission Crossmember

For the full write up on the parts please click the link below.


Say what you will about the old Stovebolts and straight axles, some Advance Design pickups simply weren’t destined for small-blocks and Mustang IIs. It’s really kind of refreshing to see a nicely done, subtly lowered 1947-1953 Chevy pickup still riding on parallel leafs and an I-beam with a hopped-up straight-six under the hood.

Those devout inliners aren’t all sticklers for originality when it comes to the remaining two-thirds of the driveline, however. The limitations of the torque tube when it comes to lowering the suspension is one thing that automatically leads to an open-drive swap—but equally a concern is the limitation of the factory gearing that really puts the early Chevy trucks at odds trying to keep pace with today’s freeway traffic. Fortunately, the 216/235 engine family affords the ability to drop the granny-geared top shifters for more modern transmissions: the popular T-5/Tremec conversion or the automatic route with a TH350 (or an overdrive with the properly set up engine). Combine that with a 10/12-bolt or 9-inch rearend, and now that old six can breathe a hell of a lot easier on the highway.

Whether you go the auto or manual route, there are plenty of options when it comes to mounting the transmission in the chassis. Jimenez Brothers Customs (JBC) just developed an all-new, adjustable transmission crossmember that not only is very straightforward to install, but allows for precise driveline placement while providing a super strong, worry-free mounting point for that modern gearbox.

Now, in the process of incorporating the new drivetrain components, in most situations you end up losing the integral bellhousing side mounts. Seeing as the engine attaches to the frame at the very front, and the transmission now locates at the very rear, a weak point has been created where the bellhousing and block meet. JBC addressed that as well by developing a side-mount kit for the 216/235s. The brackets require welding, as that allows the installer to set the engine higher or lower than stock, if needed—but since the kit uses boxing plates for the frame, a proficient welder (both person and machine) is required for the job anyway. Furthermore, the tube center portion of the trans crossmember will need to be welded to the brackets as well.

We grabbed one of the first trans crossmembers JBC finished up to install in a bare 1947-1953 chassis to accommodate a 235/T-5 using JBC’s straight-six side-mount kit. Having the cab off allows the crossmember installation to be completely bolt-in; JBC also offers a bracket configuration designed specifically for “cab on” installations, which attaches to the side of the framerail rather than the upper/lower lips, but is still vertically adjustable.

JBC offers adjustable crossmember kits for the earlier (pre-1947) and later (1955-up) Chevys as well as Ford F-1/F-100s. Because of the universal nature, other makes and models will also apply depending on framerail height. Give JBC a call for more info.

All Pictures involved with this article are available at the link below


We would like to thank Rob Fortier and Hot Rod Netwrok for the write up!

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