So I just got a 85 town car and it runs well, but I am having issues with the speedometer; The analog speedy is nearly 20mph off. How do I fix this? Do I have to just pull the sucker appart and align it, or do I have to mess with a sensor?

There could be a couple of reasons. One of them could be the gear on the end of the cable that goes into the transmission. There could be a problem with it, or it could be the cable itself. Is it making noise? If it is I would suspect the cable which is not fun to replace. Or it could be the part that connects to the dash. None of these will be a fun thing to figure out. If it were me and the car was just a daily driver I would just forget about it.