I need help Identifying the engine in an airplane I bought. It is a Gasoline powered engine, has an RCS 1000 rc showcase ignition module. It is a side exhaust model engine. The Propeller that was attached was 18x8. There is a number cast into the crank case on one side, it appears to be either an 80 or 30, but the casting is rough. The airplane that it is installed on is the Great Planes SU-31 3D Arf GPMA1412. Any info is greatly appreciated.

Thank you

Steve