Hello,

I am in the process of deciding what to do with my first car, a 68 Charger. Currently the shell is bolted to a body fixture and is being worked on with AMD sheet metal. In the back of my mind I have always been interested in making the car handle and behave well on a road course while remaining streetable. It would not be an all out racecar. I have a 470 with aluminum heads and a motor plate ready to go in the car. So now I am looking for some reference material and good advice on where to start the body stiffening and structural part of the build. This is not a restoration where I am worried about originality. This is not a pro touring build with big wheels. Here are my goals:

1. Not a drag car, not an all out road course car, but something streetable that will handle pretty good and still be able to take to the drag strip once a year.

2. Keep the K frame and torsion bars. ( not into tubular K frames and all that.)

3. Have the vintage nascar stance with proper wheels/tires.


I am completely ok with a roll cage, subframe connectors, torque boxes, etc. Just need to get educated on what is worth it, and what is not. Thanks to all who can help or point me in the right direction for this journey.

.IMO, the first consideration is your ultimate tire/rim package, decide that, and most everything works backward from there, and get back to us

I will do that. At the moment I have no idea, but I will begin to research. Thank you

i'm with JCC, frame connectors, torque boxes, etc.
also, radiator support stiffeners, and those stiffeners that are available for the inner front fender panels would be good.
if you are going a "nascar type" wheel and tire combo, i would use the 11" rear drums [those can come from a ton of different year C-body's and trucks/vans] and the big front disc brakes from any of the 73-up B-body's, including using the taller spindles.
don't listen to any of the "experts" that tell you the taller spindles "over extend" the upper ball joints, because i'm here to tell ya, that is all BS, as i have personally done that swap many, many times with out ANY issues whatsoever.
as to installing a cage, get your driver seat into position first, so the main hoop and side bars of your choice can be installed without interfering with your seating position comfort or protection.
don't forget to pad the bar good in any place your body is close to, especially your noggin, as those bars are REAL hard when bumped into.

There are 1 or 2 members here who have road-course Chargers, but I haven't seen their posts in some time; also a member with a '68 Road Runner.
Might want to look at photos of Mopars running NASCAR races at Riverside up through the wing-car era.
Might be a good idea to grab an SCCA, VARA, etc rule book depending on where/what event you want to run.
Like street/strip cars, there's a line where you have to decide how far to go - often, if not always, defined by one's wallet.
But it can also be delineated by replacing all the rubber bushings with more precise but harsher materials.
The stiffest, lightest structure you can build (within applicable rules) will make the car more consistent & quicker.

For a dedicated street car, I wouldn't consider adding a cage. It intrudes too much and creates its own unique set of issues.

A vintage nascar stance with proper wheels and tires...does that mean 27x10x15 or similar size on all four corners? In a d.o.t. street tire that will be your greatest traction limiting condition. Any easily available, reasonably priced, real performance street tires are going to be 18" or 20" diameter.

Nice handling, streetable set up that will behave well on a road course and can go drag racing once a year is pretty easy to achieve. Basic stiffening kit, decent shocks with moderate rate springs, your mostly done.

I have decades of track time
I'm one of those that built a few street/track cars. Best handling is a 70 Charger RT 440 iron head with an automatic. Lot's of converter so it comes out of the turns HOT. No cage but real seats/seat belts etc. Mine run under the number for a good lap time at watkins glen on street tires, no cage. 26 inch tall 10 inch wide tire on a 16x8 wheel. Z rated full tread tires not track tires. Track tires would cut the lap time better than any further mods and they do well. Even top speeds increase.

Old cars that run good laps get a lot of attention...

I have no idea of your budget but it better be big.

Biggest mistakes: too large of a tire, all 4 not square.
Not enough unibody welding - seam weld the entire car, i am not kidding
Add the us car tool reinforcements - all of them and if you were really serious i would tell you some secrets
non adjustable shocks,
too much t bar and spring rates
so much more

Look for subframe connectors specifically designed for the B-body Mopar platforms, as they will fit better and provide more rigidity.

speaking of subframe connectors, i installed [finally !] a pair on my charger over the winter, and what a difference they made ! [and they were just the bare minimum 2x2x1/8" wall tube]
i tied the [bucket] seat floor reinforcement[s] into them, plus the 1/4"x2" driveshaft loop.
this coming winter, i plan on connecting a couple of 2x2x1/8" tubes from each subrame connector to the rocker panels, and installing torque boxes.

Is it a stick or auto? I have seen some stick cars crack the various things frame wise. Build up the frame structure to handle the abuse the drive train and driving conditions will put on it.

it's an automatic car.
the connectors really tightened up the feel of the car.
not sure how much the tie-ins to the seat brackets and driveshaft loop helped, but i'm sure they didn't hurt. they were easy to do anyway, so i figured, why not ?
as to the outriggers to the rockers, i am going to have to start at 2" and taper it down to the rocker thickness/height of approximately 1 1/2-1 5/8".
i will also add a 6" long piece to the end of the outriggers that attach to the rockers to spread the load.
i will also extend the connectors from the torsion bar crossmember to the front subframe, and possibly tie the torque box plates to the extended connectors.
also considering adding a 7/8" rear bar to go along with the factory 15/16" front bar.
question on adding the rear bar is, would it be better to attach the bar to the rear housing or the body ? which would be more effective ? [sprung vs unsprung weight]

Bar on chassis gives lowest unsprung weight.

If you have the outer rockers off, consider adding a reinforcement like used on convertible cars.

thanks for the response on the rear bar mounting.
would the 7/8" bar size work ok to compliment the factory 15/16" front bar ?
as to the rockers, i won't be cutting the inner panel off, as the car is virtually rust free, or i would definitely add a convertible type of structure inside them.
that is why i have elected to add a stiffening "strap" of sorts to the end of the outriggers i plan to install.
however, i could possibly run those "straps" the full length of the inner rockers.
i wonder if that would work any better than just a 6-8" "strap" at the end of the outrigger bars ?

Balancing bar sizes is a crapshoot. Lots of other variables like tire sizes, spring rates weight balance etc need to be sorted out first.

Generally bars are a final tuning step once the rest of the package is sorted out.

I will say that the pre 70 front bars need to be considerably larger diameter due to their design. Really long lever arms compared to 70 up.

What is your budget? Without that information this is just conversation at best.

With the car on the rotisserie you have a perfect opportunity to weld up the car - this can be successfully be done without the addition of a roll cage as i built a car that handles flat without a cage
As far as suspension choices etc $$$$Budget$$$$ please and i think you may be a bit off course in unibody stabilization theory and sway bars

YUP, meaning one bar often tunes to correct the other bar.