Possible Engine Swap (617 to 616) / Body Swap

[BradenFinney]

Hello,

As silly as this may seem, I have a question about swapping a 4 cyl 616 engine into a car originally with a 5 cyl 617 (with turbo).

The background is that I have a 1982 240D that ran and drove perfectly. Automatic transmission, 616 engine, no complaints. Unfortunately it was wrecked and the inner/outer driver's fender, hood, and radiator core support metal work all need replacement. Also add to it the glowplug relay wiring, headlamp wiring, and a few other odds and ends from the wreck. The transmission linkage is also now misaligned (can't find neutral from inside the car). Everything else seems okay and the car can still run and drive.

I have found, after two years, a donor car in the right price range. It is a W123 300D turbodiesel (four door, not a wagon). The body is in "perfect" shape for a 1983 car (similar amount of rust spots to my 240). This car has a complete 5 cylinder engine and turbo, but I was told it has no compression. Assuming we discount this engine as a total loss (which is probably premature), I have two options:

1) Cut apart the perfect 300D body and slap it onto the 240D. I have 0 experience hacking apart bodywork and no welding experience. I don't really like this option.

2) Remove the 4cyl, the auto transmission, and the rear axle from the 240D and slap it into the 300D. If I go this option, given that I have all the body components of both cars, am I likely to run into any issues? All I can find on the forums is fitting the 5cyl into the 4 cyl space. I assume that my complete drivetrain would drop in, but I am a little uncertain with how the subframe/ engine mounts will line up. Were there two factory positions drilled into the car to specify where to place the subframe/mounts? I want to make sure that I'm not missing anything major or that I would need to source any other parts to make the conversion work.

I know that aside from the powertrain differences, the 300 and 240 have "gizmo" differences (manual windows in my 240, sunroof and electronic windows in the 300).

Any guidance on this would be greatly appreciated!