I believe the Baby Spitfire is of .045 displacement. They also made a Spitzy .045 with tank included (see pic...reverse pitch prop for pic only). There was also an .049 (several actually..second pic) and the "Royal Spitfire" .065 (3rd pic).

The Baby Spitfire was made to use an external tank (not connected to the engine). It would be an excellent engine for one of the many Scientific "Hollow Logs". You mount the tank in the fuselage and run tubing up to the engine.

The engine was made about 1950, give or take a few years.

I would not use the metal prop. I would try a 6x3 wooden prop...because the crankshaft is small and you wouldn't want to bend it. Use 15%-25% nitro fuel with 22%-25% castor oil lube. If it is new, break it in properly. Remember, this is OLD technology.

George