Going to use a Cessna 336 undercarriage or something more robust? The 336 is the fixed-gear predecessor to the 337. If you were working with the Hawk/Testors 337 kit in 1/48, you could probably use the main gear from the Monogram Cessna 180/185 (have to form your own spats or adapt them from some other kit) and a Cessna 172 nose wheel and spat. In 1/72, I'm not sure what to suggest unless there's a Cessna 182 or 205/206 kit in that scale.