RE: Seagull Gee Bee Z
RACJ, the Saito 170R3 weighs 46 oz. plus about 4.5oz for the exhaust ring. I have one in my Gee Bee Y and it does quite well. It ended up being one pound heavier than the Saito 150 I took out of it but the plane didn't seem to mind it. I had to move the battery as far back in the fuse as I could get it and add four oz. of lead. If your flying scale with some normal aerobatics it does fine. The sound is killer. I also put a radial in my T-28. A Saito 90. I love the sound.