IIRC, the 124 chassis used two different transmissions. The 300E's and everything above (E320, E420, 400E, 500E, etc) used the larger transmission built for the V8. The 260E and all of the smaller variants that never saw the US had the smaller tranny built for the 4 cylinder and small six. That doesn't mean you can't put a V8 or 3.2L M104 in your car, you just might also need to upgrade the transmission. I doubt if the differentials were different.

I'm sure I'll be calibrated if my memory isn't serving me well.

someguyfromMaryland