IMO, Morgan's makes the best, most consistent fuel. They make Omega which is a total synthetic oil mix, and Cool Power, which is a castor-synthetic oil mix. They also make other types, including Sidewinder racing fuel.

Cool Power should be used in ABC/N engines, and Omega can be used in ringed and lapped iron piston (are there any still around?) engines. You can run anything from 5%-15% nitro in your sport engine.

Dr.1