I usually do this with used cars I buy. I'll get a case of 10W-30 (you should prolly use 5W-30, but use whatever grade you've been using) Mobil (the cheap stuff), a couple of filters, and a couple of bottles of CD-2 Oil Detergent. Do the change, with one bottle of CD-2, then drive it around with some good revs turning for about 1000 miles. Then change it again and repeat. Each time the oil will probably come out very black. This is good, since that's what the detergent is in there for: to remove and suspend dirt particles. Finally, go get Mobil-1 sythetic oil and a filter, change it for one last time, and you should be good to go. This has worked wonders for my 3 cars, all of which I bought used and got some sludge out during a change until I did this. I know it works, since I've pulled the valve covers on each car afterwards, and every part (even the springs!) was bright & clean. Good luck!
------------------
Capri306, Moderator, The Mustang Works Online
1979 Mercury Capri, 5.0L -- C4 -- 2.73
1987 Mustang LX Notch 