I should have more closely inspected the underside before I forked over my cash.
That is, I should have used an awl to poke the metal more agressively. I discovered that while most of the crossmembers and spars look good, there is some cancer eating parts away under the undercoating...

This evening, I climbed under the car to look for the problem areas in the fuel line and found some trully frightening rust under the driver's side. The floopan is in very poor shape - almost gone, but it's the structural rust that my poking and proding revealed causes me a lot more concern.

The front DS crossmember is actually intact, but the long transverse crossmember is rotten on both ends. The front half of the spars are also excellent, but under the driver's side they start to break down quickly. For a unibody this is pretty serious (obviously). When I attempted to jack the DS front using the correct mount point, the crossmember pushed upward. Quite serious.

I need to track down someone who can do a passable patch and replace job on the midsection of the DS spar and the transverse crossmember without charging me an arm and a leg. Any suggestions for an affordable a metalworker in St. Louis? I'm thinking that properly welding in some larg square tube stock would do the trick until I can get things adressed more comprehensively.

I shoudl note that if I open the driver's side door, stand on the sil and hop up and down, there's no sign of structural collapse or movement aside from the car rocking a bit on it's suspension.


-----------------------------------
Other, less-serious discoveries.

-Headgasket is leaking some. There's a bit of "milk" in the oil.

-The car was originally Gold (all of it, both the engine compartment and under-trim metal in the tail are gold)

-The car spent some time in a barn. I found some seeds and hay in the rusted out transverse crossmember.

-The fenders appear to be original to the body (not a patch/weld job).

-The engine runs very well.

-The rear differential is leaking some at the bottom.

- the remaining metal fuel lines are wobbly and "sparked" against the starter (holy cow!!)

--
1967 P220 (My every-other-daily driver...), 1972 145S (1993-1997), 1973 1800ES (2006-Present), 1977 245 DL (1993-1999), 1983 245 (1998-2001), 1986 745 GLE (1997-2005), 1990 745 GL (2003-4), 1995 945 (2005-Present)....
What's a "Sedan"???