what year is it? I think in 81 they switched to electric over hydraulic, alot easier to run. Also some where in there they went to the 466 from the 436, which feels like alot more then the 20 horsepower they claim it added. Maybe the 466 just has more torque. We don't notice much power drop from the unloader on ours...they don't unload near as fast as the newer ones so you're not using as much hp.