Barracuda sag

I have a 69 notchback that a title body work turned into a major deal. One thing leads to another. Anyway I put the car on jack stands under the axles and LCAs then installed frame connectors. I am moving onto relocating the springs. While moving the jack stands to under the frame connectors and frame at rear valance I noticed a lot of body movement as I lower the rear. With the car on frame connector stands and lowered the rear axle with no jack stands at rear body seem to sag about an inch when jack was taken off the differential. Does that seem normal to have the body move roughly an inch? I looked at door gaps and nothing seemed out of the normal.

Yes it can be normal to see some body flex when jacking, especially when jacking from one corner. As long as it comes to rest and everything looks good you should be fine. This is assuming the car is not full of rust.

akrateffil said:

I have a 69 notchback that a title body work turned into a major deal. One thing leads to another. Anyway I put the car on jack stands under the axles and LCAs then installed frame connectors. I am moving onto relocating the springs. While moving the jack stands to under the frame connectors and frame at rear valance I noticed a lot of body movement as I lower the rear. With the car on frame connector stands and lowered the rear axle with no jack stands at rear body seem to sag about an inch when jack was taken off the differential. Does that seem normal to have the body move roughly an inch? I looked at door gaps and nothing seemed out of the normal.

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Did you install weld-in sub frame connectors? What about torque boxes? Those two items should stop or at least limit what you are describing.

As mentioned above, the cars will still flex, but my convertible doesn't even flex an inch when putting jack stands on the subframe at the front spring hangers. Yes, it came with torque boxes and I welded in a complete US Cartool chassis kit into it. That is one of the structural improvements the subframe connectors provide.

How rusty is the car? Can you have someone help you raise and lower the car to see what exactly is bending or may be broken?

Have you considered installing a 6-point cage with the rear tubes passing through the rear package tray to the top of the rear frame rails?

I presume that the subframe connectors are welded in at front and back only? This is the advantage of the US Car Tool connectors that weld to the floor pan. You might be able to stiffen things up by welding in some plates that attach the connectors to the floor pan. Not the whole length, but I would put pieces in on both sides of the subframe connectors where you do, so you make a little box tube between the connector, the installed plates and the floor pan.

The frame connectors are installed. I did it with jack stands under the suspension. They are US Cartool and welded at both ends and underside the floors. I have torque boxes coming. The car has minimal rust. Full rocker and quarter have been installed on driver side. The trunk has a touch of rust but overall is solid. I have heard racers of yesteryear used to weld up the unibody frame at the joints. I want to avoid a roll cage as this is a street car.
Thanks for the input. My next step is to have a second set of eyes to see what is flexing. And weld in torque boxes at the rear.

For comparison, no frame connectors installed. When I lift the car to stands located below the rear axle spring plates and as far forward on the front frame rails as possible, I see some slight door sag in the previously rested gaps as noticed. The 383 Auto car has Factory rear boxes and no front boxes.