The "250" is a valid model for the W123 lineup.

Basically, Mercedes had the following line (available worldwide) at the first half of W123 production:

200
230
250
280
280 E
200 D
220 D
240 D
300 D

The 250 was a rare beast indeed, in most markets it sold at very low numbers, although most magazines and techs appreciated its power and reliability. Why it sold so badly then? Well, since it was a six-cylinder unit, it was more expensive than a four-cylinder 200 or 230. Most prospective buyers who were eager to fork the expense for a six cylinder would chip in for the 280, or even the 280 E.

Basically, the 250 was made to counter attack some markets were cars with displacements higher than 2.5 liters were heavily taxed (as the 280/280 E was a victim of). One market I remember at the time was Italy.

I would say the 250 on the W123 lineup was the equivalent to the 260 SE on the W126 and the S 280 on the W140. Peculiar models which all sold at very small numbers.

Actually, I remember an article on the official M.B. magazine in the early 1980's that the 250 was actually taken out of production for selling so slowly and not by having a new engine replacing the specific model.

It is indeed an excellent car, although I have heard from independent techs here that parts are almost impossible to get anywhere. As I understand, the engine was a smaller block version from the 280, but many engine parts were especifically made for the 250. Not being a popular model has made availability of spare parts a mess.

Hopefully the info would help you.

__________________
A. Rosich
CL 500, 1998
S 500 L, 1998
E 320 T, 1995 [Sadly sold ]