how do i lift rear end of 1994 cadilac deville to put 20 in. rims on

If your rim is rubbing your either going to have to roll the skirts lips out or see about purchasing some heavy duty shocks that will give you another inch lift or so. I had to put heavy duty gabriel air shocks on my 67 just so i could maintain normal ride height. Also see if changing your knockoff helps,unless it's your lip thats rubbing then stick to what was said from above.

i have a 94 deville with 22 inch. rims and what i did to lift the back end up so it wouldn't rub the skirts is simple..i tapped into the factory air line and installed a air line conversion kit from autozone,giving me the freedom to lift and lower as i please!!i put in 48psi and ride..and for the front i i stuck 6 spacer blocks in the coils 3 on each side of the springs and drilled little holes in the middle of them so i could slide zip ties between them attached to the springs so they dont fall out if u hit a nice size dip

so many many hacks. I would simply make 3" Custom Strut Tops, roll fenders and trim the trim. My shop does it all for about 500$ anything over 24" and you need to modify your spring perch as it will be rubbing your tire and wheel. At my shop this generally cost about 1200$ Kultivated Kustoms https://www.facebook.com/KultivatedKustoms/