How much rust is too much

[Adam]

While you have the trunk pan out, look carefully at the shock mounting holes, front and rear, for cracks.

Even without cracks you can see how thin the metal is... I would consider tacking on some big washers to support the holes. I think modern performance shocks probably hammer away at the cross member more than original shocks.

Paharamia, your yellow convertible is going to be awesome. Save that little grommet for the fuel sender wire, I had a hard time finding one....

 

[Adam]

Martin, that is a lot of daylight! I would suggest putting the center trunk pan in, then mock up the 1/4,s with the trunk extensions; check the fit /gap of the trunk lid and weld the 1/4,s first. Because the extensions can be moved inward/outward to meet the bottom of the 1/4, and they usually need some trimming...

This is also why a two piece pan is nice, you can fit it up to the old extensions, wheel well, etc, as reference points. Then when the pan is in you can remove the old extensions and use the new pan and 1/4,s as reference points.

 

[Martin]

Yeah, this was not the plan. Previous owner had started some things in a half assed way that I did not really foresee when I bought the car. Plan is one piece floor and tail pan go back in to recreate my reference points in context with the trunk gutters. I did weld in some braces and measured everything from multiple spots. Good advice on the trunk extensions positioning with the quarters. I was already wondering and concerned about that fit. I am also doing mini tubs, so that will create even more fun in the equation. I don’t care about the shock mount holes, since I am switching to a four link. But yes one of them is ovalized.

 

[David DiMartino]

I'm a little late jumping in on this one but I just finished replacing the floor in my 73 Cuda from the rear seats back in addition to the rear frame rails. I did my frame rails one at a time so I maintained a factory point of reference. My tail panel was rotted around the taillight openings and along the bottom where it connected to the trunk pan. Word of advice on the body panels, join everything with self tapping screws and verify measurements and alignments before welding anything. It's much easier to remove screws if adjustments are needed.

I would also recommend removing the tail panel over the two piece floor. It is much easier to rosette weld the tail panel back to the new floor than to weld the long seam between the two panels.

At any rate, be patient and you will have no problem with the repair.

 

[340challconvert]

Now my work really begins!

 

[David DiMartino]

That's about where I was 6 months ago.

 

[aussiemark]

Now my work really begins!
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I don't like the look of those rear shock absorbers with the coil spring they could damage the cross member the same way air shock absorbers do.

 

[340challconvert]

I don't like the look of those rear shock absorbers with the coil spring they could damage the cross member the same way air shock absorbers do.

I know, I put them on in the early 80's
Thanks for the thought; They are now gone.
Cross member is in good shape; no stress cracks or metal tears. I am in the process of cleaning it up, top and inside and rust proof/painting it.
Regular shocks will be reinstalled.
I picked up the Mopar Performance replacement leaf springs a few years back for installation; heard mixed reviews on them.
The back of my Challenger was low even when the car was 10 years old.