Some alternators have a double groove pulley, while others might just have the single groove with an un-machined space where the second groove would usually be. Then there's a bunch of aftermarket pulleys available with a wide groove for farm equipment applications or adapting a old wide-belt stovebolt engine with an OEM generator to an alternator conversion. BTW, the pulley and the fan are separate units- - - -once the nut is removed, they can be separated, so any pulley you want can be added. All you need is an impact wrench. Friction alone drives the armature- - - -there's no keyway in the pulley or the shaft.
The adjuster bracket can fit on either side of the housing ear, but it might interfere with the fan if it's placed in front.
Jerry
