Power Steering Question

My 74 is currently manual steering and I want to convert it to power. I've found a few kits online that are around 500 for the pump, box, hoses and pitman arm. I priced those parts at Autozone and for all those parts its only 300. Am I missing something here? Is this going to be more complicated than just buying the parts and installing them, are there other components that will also have to be changed?

 

Your manual box will have 3 bolts holding it to the frame. Most power steering boxes have 4. A lot of people just use three in the power box and seem to work just fine. You'll also need a bracket to mount the pump to the engine. I got mine from a mid '80's Buick Regal. The manual steering pitman arm won't fit on the power steering box. And I believe the spline count on the input shaft at the box is a different spline count than the manual box. These are all pretty easy things to figure out. But it's just not as simple as bolt it all together. Is it ever?

 

as mentioned by Posi, the pitman arm is diff diameter as well as the intermediate shaft between the box and the column.
if you could pull it all from a boneyard Jeep, that would be best $$ wise

 

A TJ PS box bolted directly in place of the manual box on my 72. This includes the connection for the steering column. The stock TJ pitman arm acts just like a 4" drop pitman arm for a CJ in this application. I already had the pump and bracket when I swapped in a '83 258 so I can not help you there.