[Blowd]

OK, I'm kind of learning about these pumps as I go along so bear with me. My understanding is that that the Saginaw P style pump is used in about a half billion applications. First attached photo shows it relieved of the "ham can" housing.
What Casanova is running on that Camaro is a unit modified by Lee to run "dry". That is divorced from the reservoir. This is to avoid having the hot pump sitting in your fluid reservoir. They plug the holes at the bottom and tap the top for an AN or pipe fitting. There may be some internal improvements done as well. Bottom line is your running the same style pump, just without the reservoir around it. Makes adding a cooler easier as well.
There are also some considerations for the reservoir design to reduce airation such as the shape of the "funnel" and the return line entry. As Pontirag pointed out, the inlet to the pump can collapse under suction. It is recommended to use a spring inside the hose if your not using a line rated for suction.
Back to the photo, you can also see the pressure valve and spring which is behind the inlet. These come in various applications and are a simple drop in swap. The pressure (hose) fitting itself is a male connector on early pumps and female after 67 (I think). They are interchangeable. I have not yet verified if the metric inlet fittings are interchangeable as well.
I've also included photos of my prototype for my Alternator mount. 1st pic has arrows pointing to original alternator mounting hole (68 style bracket) and the embossed area on the pwr steering bracket that will have to be cut down for full travel. 2nd photo is a differnt angle, the water neck is obscured by the straight edge in this photo. (I was using the valve cover bolts as a parallel reference). 3rd photo is looking down the water neck with the alternator mounted. Plan is to go under the alternator and over the pwr steering pump with some armored hose.
Note I still have the 11 bolt timing cover and water pump on these photos which makes it look a bit weird with the 68 brackets.
Should get my hands on the Astro Van pump set up by next weekend and I can verify clearance.