Subframe connectors for a driver/cruiser, necessary to weld to floor?
- Thread starter hotrod swinger
- Start date
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Rat Bastid
Dunamis Metron
It does look like they require more fitting. That’s not hard. I can weld overhead. So that’s not an issue either.
moparmat2000
Well-Known Member
I have done 2 cars with 2x3 and lap plates on the torsion bar crossmember. Plenty strong, and cheap to do.
Discussing and cussing subframe connectors is like a politician or brain surgeon
recommending a brand of motor oil!!
moparmat2000
Well-Known Member
Heres mine. Slotted at the rear and overlapping the framerail. E brake cable rerouted inboard of the connector so it runs parallel to it. I have seen people make big gaping slots in the connectors for cables. It kills the strength and looks like ***. I fitted this with a 4 speed setup. It clears the Zee bar well. Note the homemade torque boxes.
golden boy
Well-Known Member
i welded 1 x 2 x .100 req tube "Under" the stub frames @ front and back creating a box with the body. about 12-16 inches of overlap allows plenty of welding space on both sides. 67 Barracuda runs 12.6's 2 the track, leaves straight, no noticeable flex.
I didn't cut the floor on my 67 barracuda. I just bumped it up a little and plug welded the floor to the connector at that point.
The USCT subframes are just a ton more labor intensive. The fitting isn’t terrible, or at least it wasn’t on my Dart that I installed them on. I did have to do some grinding and fitting but I expected that part. The welding overhead thing sucks, I did mine with the car elevated on 12 ton jackstands so it really wasn’t high enough to be comfortable. Slag falling on you etc. Plus the welding isn’t super easy, it’s just sheet metal and there’s a pretty substantial difference in thickness between the USCT subframes and the floor pan. And some of that was how I was doing it, I didn’t fully strip the car I just wire wheeled the weld area, my welder is a Millermatic 15 from 1972 so it doesn’t have all the automatic settings etc.
I made my own 1.5”x3” connectors for my Duster, even building them myself it was less work than the USCT ones. And the Duster still had a noticeable improvement in body stiffness. I’m not gonna say one style of connector is better, you’d need a full on finite element analysis or destructive testing to know the answer to that question, from my perspective both styles work well. I know for me I wouldn’t do the USCT ones again unless the car was fully blasted and on a rotisserie.
lead69
hopeless car junkie
Fwiw I really like the hotchkiss subframe connectors although they are normally a bit expensive (I got them on a clearance sale a while ago) compared to making them yourself. They are great for someone who doesn't have the desire (like me/ limited time and lazy lol) to fab their own, they fit great with no floor issues.
I'm getting close to installing USTC subframe connectors on my '65 Barracuda FS project. The reason for installing them is to (hopefully) eliminate the body flex that causes cracking at the base of the rear window. My body man did put extra welds in the corner joints, but also encouraged me to install subframe connectors. I've got a lot of $$$ in this car and don't want to risk the return of the cracks.
Do not weld the support bars to the floor pan, ask me how I know
Isn’t everyone that uses these ones say there the best because of that?
What did you use there? 2" x 3"? you did a real nice job! Perhaps what the factory would have done. Certainly what they should have done!
Pretty easy to see which way is best. Look what the factory did with the frame rails they used. Had they made these cars with full frame rails, they certainly wouldn't have left the center rails hangin in the air, would they? lol I really like what @moparmat2000 did in post #80. That really looks factory.
Ya, that’s awesome. Kim
I have a 1980 Dodge D150 and I'm having trouble finding anyone that makes frame connectors for it ..... 
dummyI have a 1980 Dodge D150 and I'm having trouble finding anyone that makes frame connectors for it .....
No, it is not easy to see what's best. Comparing a spot welded, thin wall open box to a thick wall tubular connector is not obvious, if you understand how those are loaded.
As I have said before, unless you're going to do a full finite element analysis, which type is stronger is a wild *** guess. It's a guess for me, and I have structural engineering and materials science education. So whether you admit it or not, you're just guessing. You've got no idea which is actually stronger.
I was talking about it's best to see what the factory might have done. Not necessarily what was strongest. I stand by what I said.
DionR
Well-Known Member
Please clarify
I have welded in 2 x 3 tubing for frame connectors for years in lots of Mopars and a few Fords. I have never tried to do the thru floors deal as I have to lay on my old back and do it all. I too have no idea what is the strongest way, but what I do sure makes it stout!!! Makes a REAL difference. But then I have heard some "arm chair engineers" say the car needs to flew some!
Don't know!!
Don't know!!
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