Chaz, some of it depends on what axle you have............for my Dana 60 they (local 4WPW) recommended the 9118, and for my rear 14FF recommended the 9012 looooooonnnnnngggggg shocks. Someday might upgrade the front to the F250 shock towers and go to the 9012 up front, but for now am running the 9118.
They recommend you measure from eye to eye, then they can tell you which shock to run...........that's what they did for me anyway.
<font color=blue>'79 ONE TON TPI K5 - See it at---><A target="_blank" HREF=http://www.blazzinor.alloffroad.com>http://www.blazzinor.alloffroad.com</A>