I was at a local Porsche track day a few years ago watching a friend of mine. I was checking out some of the GT type race cars and they had welded all the seams. They also welded the top of the cage to the roof. Never saw that before.

I did 2"x3" .120wall connectors. I welded the fronts to plates, then to the trans x-member, the backs got sliced and folded up to meet the stubs of the rear frame. There wasn't a lot sticking out in front of the 72 h-code (340 stick) demon torque boxes. Mine are not welded to the floor at all, mostly b/c I already did a full interior w dynamat and didnt want to do it all over again. Like everybody said, night and day handling, squeaks, rattles gone.

I did a ton of seam welding on project Charger blacknblue as well as adding the subframe connectors and the "rust repair boxes" to the front frame rails where the torsion bars live.

Some one out there welded up an a body and it worked!

Cop cars got 120 extra welds
it's in the cop car brochures
Aspen/volare/M body cop cars got gussets as well

I decided to go ahead and make my own. I used the same type 3x3 .120 wall tube stock that I used on a Duster project. I didn't want to cut the floors, so I made cuts into the tubes to match the floor. I then welded in the open areas to "box" the tubing. They are welded on 3 sides at the front and rear. I also made my own torque boxes out of 14 guage sheet metal. I suppose that the factory torque boxes were built with thinner guage metal, but since I wasn't sure, I just went with what seemed right. I had to reroute the fuel and brake lines since the frame connectors covered the holes that they passed through. Its not fun welding under a car that is on jackstands! While I am fortunate to be in reasonable physical shape, it is still cramped under there. I popped 3 light bulbs from weld spatter. Dang CFL bulbs....THANKS Al Gore....
I'll post a few pictures soon.

Heres a pic of thre xv connectors... I wasn't impressed with the fit at all, they took a ton of grinding to fit. I did smooth them out with some polyester, but afterall the work they did turn out nice. After installing these, my challenger will get some square tube and cut into the floors.

I made the conversion to my Lincoln MIG welder from flux core to gas. I was quite happy with the quality of welds compared to the flux core setup. I've found that overhead welding is a little more difficult though. The nozzle tends to trap falling spatter or slag, causing a flow restriction of the gas. I'm sure that there is a way around that. ANY suggestions?

Franken...its all in the setup of the machine. You dont want much spatter or slag...you want the weld material sticking to your base material. I know it sounds obvious, but this is MUCH more critical when doing overhead stuff. I HATE it, but only because I dont like the sparks landing on me...I can still weld pretty nice.
Where in GB are you again? Maybe I can come by...it would be nice to meet someone from the forum anyways.

That nozzle snot? grease or whatever it is seems to help, at least to remove the splatter you are talking about

My welds on level or overhead positions are decent. Its the overhead stuff where I really need improvement.
Nozzle Snot? Is that a product available from a welding supply? This is my first foray into MIG/gas welding. The Flux core had no nozzle to clog. The overhead welds were a little easier that way.
Over the years of working on cars, I've often wondered if my occasional poor results are the result of my limited skills or bad materials/tools. I'm always willing to learn a new method though.

Yes any welding supply should have it, its also more properly called Nozzle dip. I think the problem you are having is multifold, dirty hard to clean welds, and the toughness of welding thick to thin, overhead, out of position is just not easy, skill/practice helps, but its still tough.

Franken, I use Nozzle spray...I dont like the dip because it drips out of the end of the nozzle when you pull it out of the "tub" it comes in. I use a spray. I spray the material and the nozzle on the gun. As you mentioned, welding on old, dissimilar metals is probably your biggest problem. There is so much crap imbedded in old material, even though it looks clean, it is still usually contaminated to some degree.

The horizontal and overhead welding allows the weld to "Build" as I move along, but the overhead areas tend to drip out even though I tried several different settings on the welder. Falling globs of melted metal scare me a little.
I see what you mean... the welding of new & uncontaminated metal to 41 year old Detroit steel could be an issue. On the workbench, welding 2 new pieces together, the welds look great and the beads are not irregular or "Popcorn" like at all. I ran a knotted wire wheel on everywhere I intended to weld, so at least the surfaces looked clean. Its done now though. To finish the trouble areas, I had to do a series of quick ZAPS, then tune it all up with the 4" grinder.
This isn't the last car that I will do, so i am still interested in any other suggestions anyone has. Thank you all!

I'm a big fan of cheap and quick 2x3 tubes through the floor.

Quick and Dirty Subframe Connecters on the 1967 Plymouth Valiant

Quick and Dirty Subframe Connecters on the 1970 Dodge Challenger

Check out these bolt in frame connectors - http://unlawfulracing.com/FrameConnectorKits.html

US Car tool and Auto rust techs torque boxes being installed on Sinnamon. I have MP's on Black Betty... they were good for the day. Had and returned XV sfc's.... they didn't fit at all.

from the other end.

Quote:

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However, the rocker panels aren't thick gauge steel.

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Here you are wrong, on my 70 Challenger the rocker metal is much thicker than the rest of the sheet metal. I know because my rocker had a big dent and I cut out that section to put in a replacement patch. The patch was regular sheet metal thickness and I ended up beating my original section straight and welding it back in.