I'm probably going to provoke some strong opinions here, but I have had a number of OHC engines-3 Mercedes among them- and I am hard pressed to grasp the advantage of OHCs for a passenger car motor vs a well designed pushrod engine, of which US manufactures have long been the masters. The OHC engines are more expensive to make and maintain, often have cam chain/belt and follower wear issues that pushrods engines don't, and offer little if any efficiency advantages over (and I stress this)a well designed pushrod engine. It's almost as if Mercedes and other builders of high class cars consider the pushrod design beneath their dignity. A case in point: the Buick (GM) 3.8 V-6. Light, compact, efficient, and bulletproof, especially the series II engine that came out in 1996. And the supercharged version makes serious usable power all over the rev band. 250,000+ no hassle miles is considered pretty ordinary for these engines, and there are other American pushrod engines that are just as good. Of course, the US auto industry has been moving away from pushrods lately too, but that's probably more a matter of sales gimmickry than engineering necessity. Maybe the US auto industry should be religated to making engines for the rest of the world!

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Berfinroy in CT
Present vehicles:
1973 300 SEL 4.5
1959 Rolls Royce Silver Cloud I
1959 Ford Thunderbird convertible/430
Past vehicles;
1958 Bentley S 1
1976 ex-Max Hoffman 6.9
1970 300SEL 2.8
1958 Jaguar MK IX
1961 Jaguar MK IX
1963 Jaguar E-type factory special roadster
1948 Plymouth woody
1955 Morgan plus 4
1966 Shelby GT350H Mustang