Originally Posted by tomscat1

I am about to start restoring my 1975 W115 300D. I will be doing a leak down test to try to determine the cause of my excessive oil consumption. If it just needs top end work, I will either redo my current cylinder head, or use a spare head from my former 1976 W115 300D.

If it need bottom end work in addition to the head work, I will be in the same boat as you.... Looking for a good replacement engine.

The W115s are, of course, fairly hard to find. The early W123s (pre-turbo) are pretty similar to the W115s. You appear to think that they wont work. What is your basis for that conclusion.... Assuming that is what you believe.

While there are slight differences between the two, I disagree with that conclusion: I believe it will work. If I do need to replace the engine, and if I can't locate a W115, I have an early W123 available that I plan to buy and swap in.

I am interested to know your thoughts, in case I have overlooked something. Although I think I am correct, I could be mistaken. I would much rather find out sooner than later.