I have never previously commented on this thread and posts therein. I know exactly what CraigS (sorry we don't hear from him any more) is talking about. I can take his observations a little further. Many years ago I owned a LWB 300SEL, 1966 vintage, with that venerable 300 six cylinder engine started in the 1952 (?) Adenauer model, perpetuated by the Gullwing engine (ca. 1956), then the 300SL (from 1961 ?) Sports car and then a succession of Saloons and Coupes right up to 1967. In the early years, the 300 was a cast iron engine block, and fuel was handled by a twin element fuel supply arrangement but, over a period of time, the block was cast from Alloy with Wet Liners, and the Head was an angle fit with Combustion Chambers in the block - can we talk about P5 Rovers with Overhead Inlet and Side Exhaust Valves, with combustion chambers also located in the Cylinder Block ? I wonder, but I know for sure that the Mercedes engine was far more highly developed.
The 300 Mercedes arrangement was called a "Heron Head", and the whole engine was an absolute monster in exterior size with a six stage element Fuel Injection Pump, plus an Oil Temperature controlled viscous coupling free spinning fan arrangement and that famous Water Pump being located deep down at the side of the Cylinder Block, driven by a flexible coupling attached to the back of a huge Generator. I have seen that Generator fitted to some heavy duty Military Vehicles and also Light Trucks . On this 300 engine, Intake and Exhaust Manifolds were located entwined with each other, and with my car, there was also a large York Compressor also located on the same side and attached to the Cylinder Block by a huge, heavy duty bracket. In addition, there were also Water Pipes, Jackets and water hoses at the same side and working on those engines was not for the faint hearted - in fact a nightmare. That 300 engine was discontinued in 1967 on account of prohibitive manufacturing costs. I also remember that in about 1978 or so a Distributor Cap would retail for $AUD 500.00, and at one stage I forked out $AUD 1300.00 to have the Starter Motor rebuilt - but, it was a great family car with self levelling suspension and the faster you drove it, the better it went. Some years ago, I believe, there was only one such 300 LWB Finnie on the road in Germany, and it was valued at $AUD40,000. Regards Styria