Subframe Connectors and Torque Boxes - Installation Instructions

[Dray]

Hello everyone,

I am dropping a fuel injected 426 hemi <turned into a 700hp beast from ForHemisOnly> into my 72 challenger and with the increased hp and torque, some stiffening of the frame is definitely required.  So I picked up some subframe connectors and torque boxes and I am going to be installing them shortly.  I have never did this kind of work before, but after googling the topic I found the following article.  It feels fairly complete, but I just wanted to ask if there was any other things/gotchas that I should look out for while working on this project?

http://www.moparmusclemagazine.com/projectbuild/mopp_0612_classic_barracuda/index.html

Cheers,
dray

[360 'CUDA]

A good roll bar will stiffen up the chassis too but even if you don't want the hassle of a bar there are some areas that you can reinforce.  First, you can weld up the seam on the floor behind the front seats. Also, add some welds and maybe a gusset or two to all four corners of the engine bay on the top where the fenders bolt on as well as the various brackets that attach to the firewall and sheerpanels.  These areas tend to crack and twist when unruley torque and horsepower try to tear them apart.

If you don't care about cutting your car you can use 2x3 steel beams that pass through the floor and weld them to the back of the torsion bar crossmember and to the front of the rear Longitudials (that's Mopar speak for frame)
If you do cut the floor make the slot the connectors will go into a little bit smaller then the actual steel connector. Then use a rubber mallet to force that dude through and weld either side of the floor to the connector where it goes through. They should go right under the front seats and not interfere with the seat brackets

I actually kinked out the drivers quarter and tore the floor on an Aspen I used to race because it had no modifications and that was with a small block!

[Dray]

Hey there 360cuda,

Thanx for the feedback, anything I can learn going into the frame stiffening project is going to make my life easier in the long run.    This might sound a little crazy, but I actually didn't want that much hp in the hemi    and I don't plan on racing it.  I just wanted to make sure that when I ran into a Grand-AM <painful story that started this whole powertrain upgrade> who wanted to play, I would leave them admiring my taillights.  So on that note, I don't want to cut the car unless I am absolutely forced to. 

In any event I am definitely going to pursue the reinforcement welds in the floor panels and in the engine bay and given enough responses like yours to my posts, I will hopefully shake my    status.

Cheers,
dray

[HP2]

While a lot of work, stitch welding all the uni-body seams will reap a huge payback in rigidity. The same applies to the k-frame as well.

Think of it this way, our cars were put together using spot welders and those spots are 30 some years old and have been exposed to weather, abuse, and deterioation. This is like having buttons hold your shirt together after being washed countless times. What rips off a shirt first, the buttons or the seams? What you are doing is supplementing the buttons by stitching the seams together.

[moper]

The frame connectors are the key. Torque boxes do very little but lighten the wallet and make it harder to reach the spring bracket nuts...lol. I use the Mancini Racing bolt ins, and weld them . I dont like wleding to the floor unless the car is still under construction, and if it's a race car, the 3x2 fully welded is a good place for a cage bar mount too. The nicest, neatest connectors are the US Car Tool ones, but they need the floors bare and the interior stripped before welding in.

[Dray]

Hey all,

HP2 - Awesome analogy, makes me want to get a mig welder and deal with all those buttons on my older shirts. 

Moper - Why do you say that you don't like welding to the floor unless the car is still under construction or if its a race car.    I am also assuming you mean the sub frame connectors when you speak of this welding.

Cheers,
dray