Power steering gear box and pump????

[66 lwb cs]

Hi I was wondering does anyone know for sure if a power steering gear box and saginaw power steering pump off of an 89 chevy 2500 would work for the power steering conversion that so many have done on here. I have a 3/4 ton 66 for reference. I found a good deal on CL for the 2 pieces but am not sure if they will work or not. Is there a specific year gear box and pump that one needs to do the conversion or maybe one that makes it easier or will any chevy truck power steering parts work for this. Also what about mounting the pump the one I am looking at still has the brackets. Would a 66 327 block have provisions for the mounting brackets or would I have to drill an tap the block? Any expert advice appreciated. I did a search but didn't find this particular info, if I missed it I apologize for a potential rehash.