in the mercedes buyers guide from 1994 they list the 86 87 300dt at 87 bore 84 stroke and max hp at 4600 rpm, max torque at 2400 with a 2.65 rear end and a top speed of 100 est. (oversquare)

they list the 350 engine at 89 bore 92.4 stroke with max hp at 4,000 rpm and max torque at 2,000 rpm and a rear end of 2.87 and est top speed of 115. (undersquare)

so it doesnt shed too much light on the high speed vs low speed engine... wait... with the lower gear, the 350 will be pulling a higher rev. at a given speed, so it would along with the other three factors that i listed before contribute to a situation where head gasket sealing can become a problem. well of course with a longer stroke comes more piston speed, and presumbably heavier parts.

btw i think that the factory probably knows what the problem is but wont own up to it. i imagine that they quietly replaced a lot of engines when these cars were new... probably head gaskets too. understandable in our litigenous society... no knock on lawyers.

__________________
[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.