Spline adapters

I'm trying to connect an auxiliary hydraulic pump with an SAE A male splined end (it's 3/4" and 11 spline) to my tractor's crankshaft pulley, which is SAE B female (7/8" 13 spline). Is there an inexpensive way to do this? I can keep it as short as I want, or can space it up to about 8" away from the pulley. Thanks.