since installing the Airlift airbag kit in Project Old School, the driveshaft comes dangerously close to hitting the top of the trailing arm crossmember when the truck is aired all the way down. For those of you that have never crawled underneath a '63-72 Chevy or occasional GMC, there is a large crossmember under the rear of the cab that the exceptionally long trailing arms on these models bolt to. On most models, the center support for the two-piece driveshaft bolts here. On some models and most hot-rodded trucks, the driveshaft simply passes through. The opening is plenty big for any and all suspension travel. Once you lower the truck, however, the driveshaft rides in the upper region of the opening, and if it ever began to make contact with the crossmember, it wouldn't take long for the crossmember to slice the driveshaft open like a can opener. Another byproduct of lowering is the loss of ground clearance. The stock trailing arm crossmember hangs down a few inches past the bottom of the frame rails. And since this low point resides right in the center of the underside of the truck, it becomes a punching bag for driveways and speed bumps. A third issue arises with severely lowered trucks when it comes time to reroute the exhaust.
The factory crossmember spans the area between the frame rails, making it impossible for the exhaust to be routed along its natural path. Early Classic Enterprises' new Extreme Drop Center Crossmember has solved all three of these clearance problems associated with 5-inches or more rear drops. Not only does the new unit give your chassis 2.5 additional inches of ground clearance, its raised center hoop design eliminates driveshaft interference on trucks with a slammed stance. This assembly also provides exhaust passages to allow you to run a 3-inch dual exhaust through the center of your chassis and out of harm's way. The Early Classic crossmember is fabricated from a 1/4-inch thick laser-cut and formed steel plate to be stronger and more functional than the factory unit, and it comes with a black powdercoated finish. The new design also retains the factory brake line, fuel line, and parking brake cable passages, and it is provided with all necessary grade-8 hardware.
If you are replacing the stock crossmember with the Early Classic unit, the big step involved is removing the eight stock rivets that hold it in place and bolting the new unit in with the supplied grade-8 hardware. Since Project Old School used to be a longbed, there was significantly more work involve since the old crossmember had been moved up in the frame and welded in place. This meant torching out the old crossmember, setting the new one into place, taking a series of measurements to determine that it was sitting perfectly square in the frame, and finally welding it into place. For this we called on Jim Iiams of IMZZ Industries in Brea, California. Jim is a master welder who has been scratch-building custom lifted and lowered suspensions for trucks for many years. IMZZ Industries can perform anything from a simple lowering job and wheel and tire packages to a one-off show-quality airbag suspension - so we knew we were in good hands. Follow along as Jim installs the Early Classic crossmember. Contact IMZZ Industries or Early Classic using the contact information in the source box if you have any questions.