The cam collar and cover on the left side of the block could be replaced with a cam and an end cover from a twin Lister. Then you could set the cam timing for your auxilliary fuel supply to the intake manifold. If you ran a fuel tube down the manifold you could release the fuel into the airsteam right near the valve seat. By using an injector pump with a low pressure 'nozzle', you could introduce viscous fuels without (excessive) precipitation in the intake manifold? The governor could also control it.
Anyway, the cam could push a small air piston compressor to run the Babington atomizer, or any other timed event for 'special fuel'.
Scott E