Challenger Chassis Stiffening Questions

The car is a 1972 Challenger that is currently blown apart and on a rotisserie. When I'm not working on the car I flip it right side up and let it rest on a "table" made out of 2x4's (torsion bar cross member and rear frame rails at spring mounts) to help alleviate any sag or twist.

I have the US Car Tool E-Body kit which includes sub frame connectors, inner fender braces, torque boxes, and core support brace. I want to be very careful and make sure everything is square and plumb before I tack the parts in place. My plan is to create four legs that can be independently leveled and bolt them to the floor at the appropriate locations. I am planning on using the locating holes in the torsion bar cross member and locating holes in the rear frame rails as reference points/mounts. Leveling the car side to side is pretty straight forward but I am not sure where is the best place to check the car for level front to back.

After I have the car squared and leveled my plan is to install the doors and check the gaps, tack the pieces in place, then off with the doors and back on to the rotisserie for final welding.

I am open to any and all comments and suggestions as to what is the best way to proceed as this is my first build of this magnitude. I also have a frame chart with dimensions in a restoration guide that I inherited with the car but would love another reference if anyone has one to share.

Thanks!
Randy

I use RV Leveling jack stands for the supports. They are cheap, screw up and down for adjustments and if you add an additional nut you can make them lock in place to prevent accidental adjustment if that were ever a problem.

Available at Walmart or many other places.

They look like these.



Cousin Eddie Approved

Thanks for the tip on the RV jacks. That's much cheaper than the 3" square tubing I was considering and no fab time! I will definitely be making a Walmart run for those. I will probably add a jam nut like you suggested for added security.

Anyone have suggestions as to where is the best place to check for level front to back? I am thinking just use the door sill?

While you are doing this, a lot of the factory chassis measurements are shown in the factory FSM = Field Service Manual. I'm sure it would help you verify your chassis straightness prior to adding reinforcements.

I used the US Cartool chassis kit on my '68 A-Body convertible and added a home-built Monte Carlo bar, which really eliminated the little cowl shake that still remained. Initially I installed the subframe connectors and drove the car for a while. I could really feel the improvement in chassis rigidity from adding those, but it also really made the cowl shake noticeable on bad roads.

Once I added the rest of the stiffening kit, the majority of the cowl shake was eliminated, but it wasn't until I added the Monte Carlo brace above the engine that all signs of cowl shake disappeared. I never did reinforce the rear frame section, but I don't feel any movement back there either.

The biggest help on these old uni-bodies, is starting with a rust free, never-been- hit chassis. Unfortunately, most folks don't live in an area conducive to these cars remaining rust free.

Those stands make it easy to level. I use 8 of them so I can adjust the end extremities as well as the passenger compartment area. Door sills right next to the pinch weld will work for front/rear level. Using the FSM body alignment measurement you can then check the extremities for level against the sills.

Thanks guys. I appreciate all the suggestions and sharing your experiences.

I am pretty lucky that the only collision this car has ever had was a low speed in the yard collision with the previous owner's mother's Lexus. It hit on the left front corner and busted part of the header panel around the headlight and crinkled the edge of the fender. I have "fixed" the fender but will most likely go ahead and replace it when the time comes. I had to replace the left front half of the floor pan due to some pinhole rust but it was still solid. Just more pinholes than I felt like fixing.