The simple power steering swap turned into a major headache with this mystery box. I fought with the vendor for about two weeks to prove that they sent the wrong part and to give me a return shipping label. Ultimately, they told me they have no guarantees that the part pictured or described on their website will match the part that arrives if it is labeled with the correct part number. Since this was drop shipped and the box had the correct part number on it, then from their perspective they sent the correct part and it's labeled as a "bought by mistake" return... This is the cost of buying from a lesser known vendor to save a few bucks. I ended up ordering another box from a more respectable vendor and within two days had the correct box in hand. This one measured within 0.1" of my manual box and resulted in a perfect fit. I was also able to use the same steering coupler that was on my manual box.
Since I moved my alternator to the low mount position, I couldn't really utilize the stock 5.3 power steering pump. I ended up using a 2002 Camaro steering pump which mounts above the alternator. The only problem with this is I had to space it out to match the truck belt spacing. Luckily, LSX Innovations makes a nice adapter bracket with the correct spacing. For the belt, if you are using a truck alternator you need a belt that is 3/4" longer than a stock Camaro belt. I used a Gates K060795 and it fit perfectly. The outlet port on the pump is on the passenger side which is somewhat strange (maybe it's an interference issue in the Camaro). I decided to just try the Camaro lines and they actually do fit with no modifications. Maybe if you are doing a really clean custom installation you would want to use something different, but for me they work for now.
In the end, the swap was worth the effort and frustration because it is a major improvement in driving quality. The wheel almost felt too light at first, but after a readjustment period I feel like it is the perfect box for this style build. My old '68 with power steering had an extremely light wheel with almost no feel, but this '87 box is a good upgrade compared to that. It's still light, but has just enough road feel that you have confidence in the wheel.
