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Front/Rear subframe connectors. Best that DON'T require welding to floorpans? I'm WELDING mine in!!

We did 2"x2" in my '63. We cut open the front of the rear framerails and slid them in a bit for overlap before welding. We also welded a plate to the front crossmember to attach the tubing. It was amazing how much difference it made! I can put a jack under any corner and still open the doors! I don't like cutting up a solid car more than you need to but this is one of those mods that do nothing but improve a car.
 
Dodge 330 said:
We did 2"x2" in my '63. We cut open the front of the rear framerails and slid them in a bit for overlap before welding. We also welded a plate to the front crossmember to attach the tubing. It was amazing how much difference it made! I can put a jack under any corner and still open the doors! I don't like cutting up a solid car more than you need to but this is one of those mods that do nothing but improve a car.
Click to expand...

To make that a bit better, if you open the front of the rear subframe, slide the 2x? in 3-4 inches with a hole drilled on each side of the stock subframe & do a rosset weld each side of the subframe to the 2x? inside in addition to the weld at the front opening on the rear subframe. Really stiff.
 
biomedtechguy said:
I already have the additional factory bracing, which I understand to be torque boxes and a plate that is up front by the K-member and radiator support IIRC.
I'm at least doing the front to rear subframe connectors, and I think that is all for now.
I'm going to wait to see if I need to relocate the spring mounts, in homage to my "modify if necessary" mantra.
I'm going to get the components for the rear suspension that either are "stock height" or possibly +1" because the inverted U of the upper rear fenderwells would be a possible point of limitation on tire width, as the next pair of rear drag radials or bias ply drag tires are going to have taller sidewalls.
Ultimately if I have to, I'll mini tub the wheelwells and get my trunk floorpan "addressed" whether that means replacement or repair.
Click to expand...

The frame rail connectors are your biggest bang for the buck......on All cars with uni-body
biomedtechguy said:
So my best friend brought to my attention that the U.S. Car Tools subframe connectors require welding to the floorpans (which I knew, but wasn't thinking about). Before I began to see my car in the reference of trying to make less "invasive" performance modifications, I was all set to use the U.S. Car Tools frame connectors....
My Assassin traction bars are shipping next week, and I'm ordering my Calvert split mono leaf springs and sliders as well. So while the car is having the front and rear suspension system replaced, I may as well tie the front and rear frames together.
What brand of subframe connectors do the best job without having to weld them to the floorpans, and how drastic of a compromise is that vs the U.S. Car Tools pieces and technique?
Thanks to all of you. I want to make the order by next week, so please let me know what you think!
Click to expand...

I have done what you describe countless times....not going into the floor. A section of 2 x 4 sq. tubing welded from the rear to the front.....it's pretty straight forward and any decent fabrication shop could do it easily. They fit pretty close to the floor and "Can" be tack welded to it if desired, but not mandatory. Just be absolutely sure the car is level and supported under the wheels or suspension as it would sitting on a level floor and you'll be amazed at the difference. It's a simple job and would be the first thing we would recommend. Good luck with your project.
 
dvw said:
Why do you say not to weld them to the floor pan? That's where it all ties together creating a strong platform. In this case we have a real V code car that's about to go into no mans land. Part racecar, part street car, and a car that is probably worth good money in stock condition. Ah what to do what to do, that is the question.
Doug
Click to expand...

I agree Doug...although most people will get enough strength by welding them at the frame rails only and not the floor, welding them to the floor is pretty much mandatory on higher horse power cars......like yours. We run a 23t alcohol altered with solid mounted rear and torsion bar front and it beats me up pretty good. I recently drove a friends 4-link car and it was like a cadillac.
 
I've owned the Dart for about seven years and recently updated the interior. While the seats and carpet were out I had USCT SFCs welded in. It's been back on the road for two weeks and its a noticeable difference. In the beginning I thought it was me just expecting to feel a difference. Yesterday I took the Dart on its first long trip, 75 miles roundtrip to and from work. I'm on the freeway and I look at the speedo and I'm doing 85 mph. In the past, 85 felt like 85 with all the squeaks and moans. Yesterday, not a peep. BTW, the Dart has a 360/380 hp crate motor so you don't need mega hp or torque to appreciate SFCs.
 
biomedtechguy said:
So my best friend brought to my attention that the U.S. Car Tools subframe connectors require welding to the floorpans (which I knew, but wasn't thinking about). Before I began to see my car in the reference of trying to make less "invasive" performance modifications, I was all set to use the U.S. Car Tools frame connectors....
My Assassin traction bars are shipping next week, and I'm ordering my Calvert split mono leaf springs and sliders as well. So while the car is having the front and rear suspension system replaced, I may as well tie the front and rear frames together.
What brand of subframe connectors do the best job without having to weld them to the floorpans, and how drastic of a compromise is that vs the U.S. Car Tools pieces and technique?
Thanks to all of you. I want to make the order by next week, so please let me know what you think!
Click to expand...
Remember dont need sub frame connectors
 
I put Hotchkis kit in when I put the Hemi in. They weld in but not to floor pan.

791E4A80-A5E5-4662-B9A8-7595F938A8F8.jpeg
7441CE0C-455F-446A-9E27-7CD424B4A565.jpeg
 
440 Charger said:
Now you are full of crap weld metal to make it strong no way.
Click to expand...
You must be a beginner sonny! We weld Subrame connectors to the subframes. Please don't try to compete with me More then two hundred cars built, you show your limited intelligence and I don't want you to over work yourself. Please bolt your connectors in and be happy with the twists and creeks you will have. Also use panel adhesive to glue your pans as well. Or try wire tie's. People don't weld floor pans to frame connectors. If your looking to improve the Floor pan performance, controlling twist and flex in pans then weld 90 degree L to the sides of the frame connectors, then lay the pans on top of connectors flush and spot weld the pans to the connectors. But please do not cut the pans and place the frame connectors cut thru the pans. We are taught in Navy welding school to always layer panels on top and join. You will be amazed by the performance.
 
Last edited:
snakeoil24 said:
You must be a beginner sonny! We weld Subrame connectors to the subframes. Please don't try to compete with me More then two hundred cars built, you show your limited intelligence and I don't want you to over work yourself. Please bolt your connectors in and be happy with the twists and creeks you will have. Also use panel adhesive to glue your pans as well. Or try wire tie's.
Click to expand...
You must know your things very nice.
 
snakeoil24 said:
You must be a beginner sonny! We weld Subrame connectors to the subframes. Please don't try to compete with me More then two hundred cars built, you show your limited intelligence and I don't want you to over work yourself. Please bolt your connectors in and be happy with the twists and creeks you will have. Also use panel adhesive to glue your pans as well. Or try wire tie's. People don't weld floor pans to frame connectors. If your looking to improve the Floor pan performance, controlling twist and flex in pans then weld 90 degree L to the sides of the frame connectors, then lay the pans on top of connectors flush and spot weld the pans to the connectors. But please do not cut the pans and place the frame connectors cut thru the pans. We are taught in Navy welding school to always layer panels on top and join. You will be amazed by the performance.
Click to expand...
Welding a sub frame to a sub frame that must be great welding .
 
440 Charger said:
Welding a sub frame to a sub frame that must be great welding .
Click to expand...
I can send you instructions. In a nut shell get a pair of 2x3 stock fish plate the sides of the sub frames. Fit the stock into subs then cut 2 holes on each side mig the plates to the out side of the subs. Fish plate front and cut two inch hole and rossette weld the plates to subs.
 
snakeoil24 said:
If your looking to improve the Floor pan performance, controlling twist and flex in pans then weld 90 degree L to the sides of the frame connectors, then lay the pans on top of connectors flush and spot weld the pans to the connectors. But please do not cut the pans and place the frame connectors cut thru the pans. We are taught in Navy welding school to always layer panels on top and join. You will be amazed by the performance.
Click to expand...
Why would you not cut the floor and weld the entire seam? Granted its a little more work.
Doug
 
If you flush the 2x3 stock to under side of pan and flange the sides of 2x3 stock you extend the spot welded surface and layer the material ten times more strength by spot welding un cut floor pan to the 2x3 stock.
 
I weld all of mine to the floor, to me it makes for a far more solid/strong. I know that with my Cuda which has a USCT SFCs on it they are as solid as any part of the factory frame.
 
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