Body mount nuts were not installed

[JustJohn]

So here’s my situation on the 69 Impala. Looks like the paint shop did not install new trapped nuts for the mounts right above my rear shocks. Impossible to do now unless I want to rip the car apart again. I feel like I want these bolted to the body…
Looking at options, I can drill through for the correct 7/16” bolt size and come out on the shelf where the top well sits. Just do that with washers or possibly also fill the gap with some structural foam?



Other option is I can use a hole saw from above and cover it with a body plug so I'm just loading where it was originally intended.

Or...I may be inclined to run a square tube the entire length of the top well that would effectively be a shock tower brace for the rear.

[XLexusTech]

Cage nuts or Rivnuts

[JustJohn]

In this case rivnuts are not an option. I decided on 1/8" strip stock across the formed channel and top well floor.

That being said, I may have been too hasty in my assumptions and these may or may not have been floating bushings. If the were, I think they should have been bolted to the chassis anyway since it is right above the shock mount.