When my 70 280SE was fouling plugs and had gasoline in the oil, the problem was a defective injection pump thermostat. It is located on top of the injection pump where two small 10mm? coolant hoses attach. IIRC the retainer for the thermostat was held down by two slotted screws. It was a simple fix.

While doing a tune up a cap and rotor is suggested along with a valve adjustment.

As suggested, don't make adjustments to the fuel injection unless you have a manual and understand the system.