I have had a Saito 1.80 in mine for the last 9 years . GREAT eng., not too much power, fits in the cowling with just the rockers sticking out a little bit . Pulls the plane very well (after all it IS a SUPER Stearman) . I did not need to add an ounce of extra weight to balance with the 1.80. LOVE the combo. Only down side is the fuel consumption ,with the stock tank if you are not in the landing pattern after 10 min. you will wish you were.