Can subframe connectors be installed on a rotisserie during a resto?


Someone told me that subframe connectors need to be installed with the car fully assembled and sitting on all 4 wheels.

How critical is that?

I have a car on a rotisserie right now.
I don't really want to reassemble the car just to install subframe connectors.
I also don't really want to weld on fresh paint as soon as the resto is done.

Any tips or suggestions?

The body will flex as you build it and add weight. I wouldn't want to weld in additional bracing to an unloaded body and then try to hold it in that position after assembly. That would only ADD additional stress instead of adding additional rigidity.


It would be akin to jacking up 1 corner of the car with a floor jack, adding twist/flex, and then trying to weld in reinforcements in that position.

I've done it more than once, works out great, set the car up horizontal with support, frame connectors went through the new floor I had just installed.

As a note, I do brace bodies on the rotisserie.

With 70's manufacturing capability and 40 years of age, I don't think you can do much wrong. These cars were far enough off leaving the assembly line. Just because the car is loaded on the ground, doesn't make it in the right position. Could it be more right? Perhaps, but unless someone has a chassis table and the proper measurements validated, it's all a guess. Then you get to worry about subtle warping as it cools.

Burn 'em in and worry less.

goody brought up a very good point. these cars had a crappy panel fit/gap when new, so unless your car is a twisted, smashed hulk, install the connectors. when the car is ready for quarter, door, and trunk lid fitment, you may need additional slicing and metal addition/removal to get the gaps to your satisfaction. then the same thing applies to fitting the front clip. don't feel bad. it's only time and money. when my one buddy built his 55 chevy [yes i know it's not a mopar, but body work is body work], you wouldn't believe the tricks we did to get the trunk lid and tail lights to fit perfectly. there was cuts, slices, heating, pushing, and more involved. same happened with the doors and front fenders. we even rigged up a mid-evil device to actually bend the whole trunk lid in two different directions to get the curvature right to fit the crown of the quarter panels, both of which were different. after that, metal was added to several places on the lid edge, and the opening was sliced and moved around to get the PERFECT fitment. granted, this is a show car, and if something were to get damaged on the rear of this car, a stock panel would require much work to fit correctly [using his standards]. and this was on a documented, two owner, granny driven, rust free, non bumped/crashed car. your results may vary, and you may be satisfied with how the gaps turn out without all this additional work, but there is a very good reason some cars have perfect panel fitment and others do not. it's just time and effort expended. no matter the vehicle brand, i can point out flaws in panel fitment and suggest ways to make it better. will i go through that effort on my junk ? absolutely not ! and i will think your car is nice when done and applaud the effort you took to get it to where it is ! but being around body guys for 50+ years, especially experts in there field and watching them work, things just kind of rub off. you will do good on your project.

And expertise! The type of bodywork you described really takes some know how.
I don't see many shops shrinking metal these days.
I understand what you're saying though.

Thanks to everyone for the advise!

I welded my subframe connectors on my Dart on a 4-post lift, but used a transmission jack to press each rear end of the connectors very firmly against the floors and frame rails before welding.

The doors shut closed a bit different, which only 'told me' I corrected some of the 40 years of body sag.

Realign the doors if needed and carry on with other things.

One would think that you'd verify the frame alignment points were correct before permanently welding in SFC's.

All else is moot, including door shutting.

this step first ! doors are almost infinitely adjustable, especially if you are willing to take the time and effort to move the opening around some, and add or subtract metal as needed on the door itself. don't forget, any two doors from different vehicles will almost fit the third vehicle slightly different than the other two. these things had horrible quality control when new, from the manufacturer and the parts supplier.

Yes they can, be welded on to a bare shell on a rotisserie. I have done it twice now and a third time on my back with a stick welder when the car was a bare shell sitting on cinder blocks when I was a teenager.

On the rotisserie I simply turned the cars on there sides and stood up and welded them in. The car is sideways, it can't sag or flex if it's coupe. Took me about an hour including welding in torque boxes. I used the old DC connectors and did not cut the floors on the last 2 cars.

OMG the first car I cut the floors and was big deal. It took weeks/months, which I think is not worth it even today. Everything fit great all three times, don't make a big deal out of it.
I have pictures to prove my point and most of you have seen them and some has seen the cars in person the panel fit is flawless. Now I have 15000 pictures on photo bucket and it takes too long to find them, it sucks.

If you didn't have sophisticated body shop measuring equipment, how can you measure for sag? The body measurements given in the service manual provide a little guidance to check square; plus minus 1/4-inch. Other than front ride height there are not many dimensions given off the ground.

If you didn't have a 4-post lift, I thought about jacking up the car and making a 2x4 wood "log cabin" stacked box about 12 to 18 inches high and drop each wheel on top of the box. Then weld the connectors in place on your back.

If your car is all together, welding in SFC with weight resting on the tires is probably okay.

If you have it all apart, it doesn't take much effort to put it on multiple jackstand and measure for plum, square, and parallel before melting in the SFC.

With that said, does it make a huge difference, not necessarily, and most of us can't differentiate the differences. However, if you care enough to do the work, why not make it as correct as possible. Competition cars are welded together on a surface plate to ensure everything is in the proper place. While most of us don't have access to that type of jig, a little effort up front usually makes things better and more consistent over time.