I'm resto-modifying a '71 Charger and am interested to know what others have done to stiffen their frame.

Things that I'm already planning:
1. using frame connectors
2. running beads along the front subframe joints. This is more to stop moisture getting in between the spot welds as much as anything else.
3. Following the recommendations for the K member.


Other areas that I'm considering are:

The shock tower has a piece of stamped steel running back to the firewall and it looks a little flimsy. I'm thinking about replacing this with something beefier. On my car these supports were welded directly to the firewall. I'm considering putting a plate on the firewall first and then connecting the support. I'm also thinking about running 1" square tube from this re-enforced area back to the A pillar.

Possibly running a hidden roll bar along the inside top of the roof. There's a lot of material from the rocker panels that stops near the roof line. I'm considering putting something to join these supports across the roof.

I'm also considering sliders for the rear leaf springs instead of shackles. Does anyone have experience with sliders?

This isn't going to be a drag racer or autocross car. It will go to the track on Friday nights for 'run what ya brung', I do it for fun not competition. The car will mostly be used for cruising long distances and winding it's way through the White Mountains of NH.

I'd appreciate any thoughts on these ideas.

Thanks,
John

Check out XV Motorsports. They are pretty deep into frame stiffening. Pretty pricey stuff but it's a good learn. See their 4 post videos, very interesting.

The shock tower supports and extending the rockers are great ideas. Connecting the subframes together is a great drag racing move because it transfers some suspension load to the floor and most imporatantly the front subframe. As for torsional ridigity, connectors by itself is overrated.

That's what I was thinking about the frame connectors and am thinking about the roof brace and possibly something with the firewall. I'll check out the XV site but I doubt I'll go that way because as you said it is very pricey stuff.

USCartool for Connectors.

I checked their site and they didn't have anything listed for a '71 B body, I also sent an email and never received a response.

I've read that people have successfully used 2x3 tubing but had to open the rear floor. I have a plasma cutter and might just trim the 2x3 to avoid cutting the floor open.

I just used the auto rust technicians subframe connectors on my '72 charger, and didn't have to cut anything on the car at all. They're 2x2, but I'd think you'd get more rigidity from a solid, uncut 2x2 than you would from a cut 2x3... I did have to modify the connectors slightly (literally a 5-minute modification) because they were a bit long, but I think my car is a mutant


Also, I've heard a lot of people recommend torque boxes, and a.r.t. carries those as well, but I have no idea on that one. My car apparently came with them stock, or had them added before I got it, so I've never given it much thought.

That's good to know about the 2x2 - thanks. The products from the 2 vendors do look nice.

Part of the fun for me on this build is fabricating some of the parts. I have a well equipped shop and know it well enough to be dangerous

I also have a nice assortment of steel around to work with. Should be interesting