the Rancho #'s for mine are RS5000 series, frt RS5601 and rears RS5143. I think that the frts are std 4 x 4 for quite a few years and the rears that I have were for a ford application. My rears had the large bolt that went right through the frame and through the shock and the bottom was just std gmc but on a 14 bolt corp. it will just depend on the length of the shock
ron

http://s908.beta.photobucket.com/user/padresag/library/turned%20works
http://s908.beta.photobucket.com/user/padresag/library/furniture
and a little history of where I come from
http://forum.woodenboat.com/showthread.php?156542-old-boatshop-in-Steveston