I've just changed the oil in two of my cars and now have 14 litres of old oil of which to dispose. (One of them's an E Type, which takes 9 litres.) Can I mix that with gas for the Stanley? I don't see why not, especially given that I've got a forced air burner. I'm thinking of a 4:1 gas:oil mix. Comments?

I dont know about that, sounds like a good way to clog up a vaporizer tube. Someone else might have a different idea.

The air atomizing burner on the Doble Style boiler I have, according to the constructors notes, worked better on a gasoline / waste oil mix. If by forced air burner you mean an atomizing or similar pumped system it should be OK.
Cheers

I tried it @ 14:1 and it worked fine. Now all I have to do is find out what the greatest ratio is, and with luck I can run my car for next to nothing. Used crankcase oil is pretty cheap around here.