Hi Everyone, I'm a noob. This site has been great to read and learn about Macks that I've always been drawn to. I feel like I'm getting addicted with all this info in one place. Same thing happened to me on the vintage Onan generator section on Smokstak (highly recommended). I'm looking for a 6 wheel dump to putt around with and tinker on. I've been looking at 1980s R models, DM's, and now I found this U model on craigslist. I just wanted some of your thoughts on what to look for when considering buying one of these trucks. Here are a couple I'm planning on taking a look at locally: U686 5 speed with 300HP Econodyne. Is Maxidyne a better engine? http://nh.craigslist.org/cto/5042356581.html R600 5 speed w/ Maxidyne 237, price seems right http://nh.craigslist.org/hvo/5060256076.html Any thoughts on these trucks or experiances you've had with similar model trucks? - good or bad. I'm just looking for a place to get started. -Matt