Speedometer

Okay, I know I'm probably the only one who will be trying this on the '86-'87 Lesabre, but just to be sure before I go out and buy one, does anybody know for certain if you can switch the digital cluster and the quartz speedometer in the 86-87 Lesabres/PAs? I saw the digital cluster in a 87 LeSabre at a salvage yard, and was curious if I could put the digital cluster in for the quartz speedo. What extra sensors would I need to put in? Thanks for any input.