ffdq,
I tried every adaptor that I could find to mount the spinner that came with the GP Super Stearman on my G26. None worked. It seems, the included spinner was designed for an OS 120 4 stroke, which has a shorter propshaft than the G26. The spinner wasn't deep
enough to allow clearance for the propshaft.
I had to order a larger spinner from TruTurn and the reccommended adaptor from their website, [link]http://www.tru-turn.com[/link] The spinner I use is 2-3/4", AT-6, 120-slot, stock # TT-2732-B-120. The profile is exactly the same as the original only 1/4" larger in dia. and 1/2" deeper to give clearance for the longer G26 propshaft. It works and looks great! Just a little pricey though. $49.95 HTH

John