[ryanroo]

The box will bolt to the frame. its a the exact same box they used in the earlier trucks.

the 73 front drive accessories will be for a long water pump. if you have the OE set up on the 71, it will be short pump. the steering pump is the same, the pulley may be different and the mount bracket will be different. if you want to run the whole shebang from the 73, you will need to swap the entire set up from one to the other. bits and pieces dont intermingle on the front drive stuff.

there is a year break in the late 70s for steering fittings. the early ones are std. flare and the later stuff is all metric o-ring. yours should be std. and would be the same as a stock 71, so if you retain the short water pump and related brackets, the line set from a 71 would be a direct fit. the lines from the 73 will be different, but still may work.