Vintage Cars: timing on a 1978 450 SLC Mercedes-Benz., chassis number, chain stretch

Question
Hi Ron, we need to set the timing on my son's car.Could you please look up your data to see what it should be ? The car has transistorised ignition, so no points to adjust.The chassis number starts with 107 , so I take it that is what it is.
Thanks, Ted.

Answer
Yes a W107 to be exact.
There should be a tag on the left side of the car under the hood next to the radiator that gives you the specifics. I start with 5 degrees above top dead center.These cars are not known for thier gas mileage so running a bit advanced helps.  I think they also run better.  I actually tune mine by ear, because if timing chain stretch the pointer is not always reliable. WIth the car running advance to find the sweet spot, you will know, then take her out and listen for ping on acceleration.  If you get ping retard it just a bit.  You want to be just below ping level.  Have vacuums attached and make sure all the rubber under the hood is good. These cars require good consistent vacuum to run well.  I have rebuilt many of these so if you have specific questions let me know
Happy Motoring
Ron