PETERK.... I dont remember the stats on a Quadra 25, but if it isnt too much heavier than Zenoah26, it should be fine. the plane will handle the weight . The Stearman, and a mid 20`s gasser are a perfect match. Ther are several ways to save weight elsewhere if needed. I have thrown away most of my NICD packs and replaced with NIMH to save space and weight thus allowing more needed weight in other areas. like engine, smoke. etc.