The recommended engine size range is as follows:
.60 to .91 cu. in. 2-stroke
.90 to 1.20 cu. in. 4-stroke
The Cessna 182 Skylane will fly well with any of the recommended engines. The 4-stroke engines and most .90 2-stroke engines will turn a larger prop at lower rpm. This is often desirable for scale realism. Many .60 2-stroke engines produce about as much horsepower as the popular .90 2-stroke engines. Both are fine choices for the Skylane. If you use a .60 2-stroke, a Schnuerle-ported engine is preferred.