Subframe connectors

Does anyone have pictures of moroso sub frame connectors in there car is it worth it or should I buy the one that weld the entire way thanks in advance

The ones that weld to the entire floor are going to be stiffer than any other.

5.7 hemi said:

The ones that weld to the entire floor are going to be stiffer than any other.

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I am curious about that.
In theory, I can see the logic but given my construction background, I see it differently.
Here is why:
In wall and roof framing, plywood adds tremendous torsional strength. A wall with 3/8" plywood nailed to studs that are 16" on center is a rigid structure capable of withstanding incredible amounts of lateral resistance. Now compare it to a wall with 3/4" plywood nailed to studs that are 24" on center. Is the wall more or less rigid now? How about 1" thick plywood with the studs 48" apart?
Now take those principles and apply them to the floor of a car.
I doubt the the sheet metal of the floor flexes much laterally or horizontally. It may twist but I'm a bit hesitant to believe that a member welded to the floor pan would make that much of a difference. I would love to see actual data from a practical (Not theoretical) test on a chassis table.
Another factor is the concept of the point of diminishing returns where "upgrades" and changes have little to no effect except to add weight.
I made my own 3 x 3" subframe connectors and while they are not welded to the floor pans, I used seam sealer to close the gaps to make them look like they are. I did this in 2012. As of today, none of those sections of sealer have pulled away or started to crack. This tells me that either my doubts about the value of "welded to the floor pan" have merit or that I'm not driving my car hard enough to stress the chassis.



Some people that cruise their cars may have spent the money to box their LCAs, added subframe connectors and torque boxes and added gussets to the K member. While this stuff cannot hurt, they may never be worth the effort if the car isn't driven hard .

And you’re right, however, having the floor welded to the sun frame connector, torsional twisting is reduced significantly. I used tubing on my 64 Polara 500, they weren’t welded to the floor, I’m sure they helped, but in my 69 Dart GT 470 4spd Dana 60, it got welded to the floor connectors which I felt more comfortable using due to the twist of that 470.

I tend to agree Kern Dog not sure welding to the floor is any better than, say A 2x2 welded rear sub to torsion support. And I’m not sure they do much unless you do like Birdsong and go thru the torsion support and connect directly to the front sub frame. My plan is to go Somewhere in the Middle of those 2 methods and go to the torsion support directly behind where the front sub attaches and to the rear like standard.

A few years ago I had the car on the lift and I cleaned up the underbody for these shots.




It still looks about the same today, though a bit dirtier.







The goal for me was to make it look like something the factory could have done.

Funny...I look at this and see the automatic transmission and am glad that I made the switch to the 5 speed.

68-500 said:

I tend to agree Kern Dog not sure welding to the floor is any better than, say A 2x2 welded rear sub to torsion support. And I’m not sure they do much unless you do like Birdsong and go thru the torsion support and connect directly to the front sub frame. My plan is to go Somewhere in the Middle of those 2 methods and go to the torsion support directly behind where the front sub attaches and to the rear like standard.

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When I put mine in, I ran them through the t-bar x-member and into the front rail about 5". The back was extended to go past the current front spring hanger boss. That was done so I can weld the spring relocation box to the SFC's. On top of that, I made additional frames for the seats, will be Procar units, to attach to instead of relying on sheetmetal.
On the existing rails, I slit them vertically, punched holes in the side and lower walls, pulled them onto the SFC's with clamps/weld Vice Grips, made a bunch of rosette welds plus lap welds to stick all together. The t-bar unit also got material added on three sides to stiffen it up for the bigger bars.

Many of the mentioned suspension upgrades
do a shitload for handling, a lot more than you'd think
stiffening feeling, hell adding bigger sway bars both front & rear
or adding just a rear sway bar makes a huge difference
wider tires & wheels too, unless you drive like grandma does
some will argue that till the cows come home too
& they would be wrong too

even bolt-in subframe connectors are better than nothing at all
jack a car up without them, open & close the doors
then do it with them installed,
you will see the difference even with bolt-ins

albeit it's not ideal, not as good as welded in
but a night & day difference nonetheless
some here are really finicky about permanently altering their cars

most here will never push a car to the limit anyway
suspension or frame (subframe connecters) wise

it's more of a want, than a true need
unless you're drag racing it or auto-crossing it etc.

it doesn't hurt it at all
unless it's a purest deal, 100% OE resto

As others have noted, the type of connectors that weld to the cars' floor would add basically what is a
"3rd dimension" of torsional control to the body, I'd think.
Frame connectors handle the "X" and "Y" dimension stiffening, but since the floor of these cars is
a factor in their torsional design, welding in the connectors to the floor would give at least some additional
stiffness due to it being the "Z" dimension in the equation - yielding a unibody more resistant to twisting
forces in all three physical planes.

Least, that's the way my old PE background tells me it plays out....

Does anyone remember back in the day, the C pillar on cars cracking? Then the post cars (B pillar) added torsional rigidity and were sought out for drag racing.

Welding the sub frame connectors add to the overall rigidity to the vehicle. Not quite the same as welding a roll cage in, but not much different.

I have the comp engineering bolt ins, after install I did weld each end just because..

Anyway, car is put away for winter so no pics right now for the OP.
Agree , welded to the pan will give more support and if in the middle of a rebuild I would have went that way.
For me the bolt ins were a good deal since my car is done, I did not want to pull the glued down heat mat or pull the seat and carpet to install.
Even the bolt ins made a improvement in drive and door alignment.