Two recommendations--
1)
use the Forum Search feature. There are several VERY good threads on shocks, including specs, model numbers, etc.
2) Download this spreadsheet tool from my web site...
http://www.myattitudesucks.com/truck/shocks.xls. It lists current Monroe part numbers, and can be sorted/filtered by mount top and bottom, length, etc. If you have some working knowledge of Excel, you can use it to narrow down your options quickly. Monroe is a very popular choice, and it is very unlikely that they won't have something to meet your particular needs. While some may like KYB, my experience is that the gas pressure on them is too much for the light weight of the rear of a truck.