Dumb question power steering pump shaft length

[truckin 79]

I need to change my single groove power steering pump to a double groove pulley for upcoming AC install. Can I use existing power steering pump that is in the truck and just add the 2 groove pulley or do I have to change the entire steering pump? I dont think it matters but I have a 74 power steering power pump(the type with nut on the end) pump on my 79, is the shaft the same length on 1 or 2 groove psp?

[REDROCKER652002]

If I remember correctly, you can unbolt the pulley and add a two groove pulley as long as the groove lines up with the grooves in the existing pulley on the crank shaft or the water pump I am sure somebody with more knowledge than I will chime in, but my dad had a collection of pulleys that he used for different applications when he was alive.

[kwmech]

Pumps are the same--- pressed pulley or bolted pulley