Hey Guys. I've been searching all over the place as well as reading both the Haynes and Mercedes BBB trying to figure out the correct way to time my 72 280SE MFI engine. The book(s) say 6 degrees ATDC with the vac advance connected @ running temp. I've done this and the car is beyond sluggish.

Specs for earlier models say to plug the vac advance line and time @ 30 degrees (guessing ATDC???) @ 4500rpm's. My shop tach only goes to 2500rpm's. How are you guys achieving this as none of the M130 108's had tach's stock.

If it helps. I've replaced the following:
Fuel / air filter
plugs
wires
cap and rotor
Hot Shot electronic ignition + their coil

Thanks in advance