Hi,
I suggest you replace the distributor cap, they are inexpensive.
If there is too much oil inside your distributor, clean it with a dry cloth.
Add one or 2 drops of engine oil on the felt wick under the rotor.
Similarly apply a couple of drops to the external oil inlet of the distributor.
Also what sort of economy are you getting?
Have you removed the plugs and looked at the colour of the tips? The colour will tell you lots about the air/fuel mixture. The Haynes manual and the BBB have pictures of ideal plug colours.
The general thoughts about plugs and leads is that they should NOT have any resistor in circuit.
The recomended total resistance of the leads and plug tops is approximately 1K ohms.
Bob (Brisbane,Australia)
RHD,1967 early 250 SL, auto