Power steering pump interchangability

[dasbulliwagen]

Ever since I converted my truck to P/S, the pump has whined a bit, and today after about 2 years of driving it like that, it finally bit the dust. I put an aftermarket reman pump on it at the time, and it has worked fine, but now looking at prices for them again, I'm wondering if there is anything else that would bolt on in the same place and work as an upgrade, like maybe from a Grand cherokee or whatever or if I should just stick with stock. My truck is an 87 2.5 with serpentine belt system and custom resevior from a Dodge caravan. These pics are from a year or so ago, so sorry no bleeding P/S fluid pics.