My 280SL has a 3.27 diff and 4 speed shift.
It has never been in a better state of tuning (timing, AFR, WRD shut off etc.)
What I want to describe is this: the car needs to be driven as if it has its original diff in it for the idle to come to rest at 800. In other words, high revs, 4000-5000 before shifting. The car will idle at 800 when driven that way.
When I drive it for a while in a "quiet" way and shift below 3500, the car will come to idle at 500. The other day, after an hour on the highway at about 75mph (+/- 3300 rpm), when I pulled off on the exit and came to a stop, the idle was 300. Then a few shifts under load up 4500rpm had the idle back to 800.
I had previously been chasing my idle around, but I've come to the conclusion that I needed to adjust my driving style to a 3.27 diff.
Any thoughts?