I have two different sets of plans for a 1930's/40's 1/5 scale Henschel Hs 123 (biplane dive bomber, close support aircraft). One plan call for "an appropriate" engine. The other calls out an OPS 60cc twin. I understand the OPS 60 Twin Maxi (an Italian engine, 1980's vintage) is no longer available. What would be the modern day equivalent ? As you might suspect, I am not an "engine person". Thanks.

red 1 (aka Don Borton)
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Waco Brotherhood #72