Thunder Tiger F-54S
 

Early version with air bleed carb, part number 9800.

It's a used engine with good compression.

I just ran it with fresh Powermaster 15% Sport fuel, a Zinger 11x5 wood prop, an O.S. "F" glow plug, OAT was 78°F, Humidity 41%, Relative Pressure 29.98 In Hg.

I got 11,500 rpm average with the needle backed off slightly from peak. Best consistent idle without dying was around 3600 average.