Tom,

I wonder which cams you have? From the cam charts I've seen, the 3.5 and the 4.5 shared the same cam at certain times. My imported '71 300SEL 3.5 has 52/53 cams, and I've found a number of 4.5 cars with the very same cams at the local junkyards (which came in handy when I needed a replacement). What numbers are stamped on the backs of your various cams?

BTW... I've had my recently acquired 300SEL 3.5 up to 150kph (about 93mph). It will easily do much, much more, but I'm holding back until I get an alignment to hopefully remedy the vibration that starts at around 140kph.

-S