I bought my '87 v10 with the 4" skyjacker lift kit already installed, so I don't have much wisdom compared to 41Plague up there (PS guy, I've loved that orange truck since the day I joined this site) because I didn't install it, but I thought I'd throw up a pic to give you an idea, its on 33" tires & 15x8" rims. I saw your truck on squarebody.net on facebook, it looks like it probably sits a little than my 1/2 ton did before the lift. Is your '87 carb'd or F.I.?
