Get Connected
Installing weld-in frame connectors for major chassis upgrading.
by Richard Ehrenberg, SAE
In the ‘60s and ‘70s, Chrysler Corporation’s chassis design was light-years ahead of the competition. From indirect-acting torsion-bar front suspension with long-and-short arms and tension struts, to asymmetric leaf shackles, the cars were unparalleled. Even the basic floor pan and chassis was excellent: all A and E-bodies, as well as pre-’73 B-Bodies, were true, all-unitized construction. In this arrangement, many components normally thought of as “body” parts are put to work carrying loads and increasing structural rigidity without carrying a weight penalty. Eye opener: If you’ve ever seen a bare frame of a ‘60s or ‘70s GM car, you’ve likely been amazed. There’s strength in only one plane. Nothing whatsoever is there to resist twisting or bending. No wonder Mopars handled so much better than Chevys—they had a rigid platform for the suspension to work from. GMs, by contrast, were virtual rubber bands.
But time waits for no man, and even Ma Mopar has upped the ante. While Chrysler moved forward, so did the quest for platform rigidity, as Pentastar engineers became more and more cognizant of the advantages to be gleaned from extra-rigid body shells. Look under a 1973 B-van: not only is it unitized, but it has a full frame! Ditto AMC’s 1983 Cherokee. It took a few years, but eventually Chrysler passenger cars became endowed with this “best of both” construction, with the 1995 JA cars (Stratus/Cirrus etc.) being the first ones we’re aware of the utilize what has become known as “rail-thru construction”.
This same extra rigidity is, surprisingly, relatively easy to add to your classic Mopar. Simply tying together the front and rear longitudinals with some rectangular tubing makes a massive improvement for minimum coinage. But don’t be fooled: if this addition isn’t installed with a rigid, permanent fastening system (read: welded) it’s as useless as mammaries on a bull. Phrased simply: bolt-in frame connectors are junk! Clear enough, Vern?
We decided to have a set of proper weld-in connectors installed at one of the northeast’s top Mopar frame and de-rusting shops: Auto Rust Technicians in Cranston, Rhode Island. These guys have devised weld-in rust repair parts for just about every Mopar on the road. The way they do this is startling in its simplicity. They have, inverted and on a rolling dolly, the floor pans of virtually all Mopar platforms. Need a left rear rail for a ’66 Satellite? They can clone it on the spot, plasma cut and mig welded, knowing full well that when it’s shipped to you, it will be a 100% perfect fit. Auto Rust Technicians’ shop is like a 2002, high-tech and modern version of an 1880s blacksmith shop. Need a hole in a piece of steel? These guys don’t even think about drilling it. Burn, baby, burn!
Their frame connector lineup is available two ways: as 2x2” square tubing, which makes for an impressive rigidity increase with a minimum of installation hassles. Or, for full-fledged race cars, 2x3” tubing (with the 3” dimension vertically, of course) gives you maximum strength while requiring more floor pan mods to install, and, in most cases, making the installation visible, as well as “feel-able” under the carpet. We decided that our post-sedan A-body was already a pretty stout piece, so we wussed out and opted for the 2x2” setup. As usual, the accompanying captioned photos show the deal step by step, as well as what we did (after the tears dried) when we yanked up the carpet and found—ugh!—a rusty driver’s-side floor pan.
Auto Rust Tech supplies these connectors ready to install for virtually all muscle-era Mopars. We made a before-and-after test that was simple but repeatable: before the installation, we jacked up the right front corner with a floor jeack under the lower control arm, simulating, to the best of our admittedly-meager resources, what happens under cornering or drag-racing starting-0line loads. Then we opened and closed both doors. While they were operational, they suddenly seemed “misadjusted”, requiring extra effort to close fully, and acting sluggish on opening. Once the connectors were installed, we repeated the test. The outcome was startling: ka-clink! Effort, and tone, were virtually unchanged from that noted at the car’s non-jacked level stance. A road test was equally impressive, with the car suddenly taking on a “carved from granite” road feel.
For the next step up the rigidity food chain, ART is readying a line of weld0in front and rear torque boxes, similar to what the factory used in Hemi and convertible cars.
Our advice? Don’t hesitate. This is one improvement that’s more than worth the few pounds it adds.
Sources cited:
Frame connectors, rust repair chassis parts:
Auto Rust Technicians
275 Niantic Av.
Cranston RI 02907
(401) 944-4444
www.autorust.com
Floor pans, body panels:
Auto Body Specialties
POB 455
Middlefield CT 06455
(888) 277-1960
www.autobodyspecialt.com
Copyright Mopar Action Magazine, October 2002, used with permission.
In their words,
"This article originally appeared in the October 2002 issue of Mopar Action Magazine. Republished here by permission. This entire work is copyright 2002 by Richard Ehrenberg and Harris Publications, Inc., New York, NY. All rights reserved. Protected under international copyright conventions. This work may not be reposted, retransmitted, printed, published, photocopied, or otherwise distributed, whether by electronic or any other means, without permission in writing from the copyright holders. Violators will be dismembered, marinated, spiced, and fed to hungry lawyers."