Leroy I don't know what you know about 039s/390s. I'll assume you don't know and I'd like to see you get alot of miles out of your saw. First off these saws are not pro saws more of a midrange/ plastic case, homeowners grade saw and not really thought of as a milling saw. They do crank out lot's of power-I use mine on my RipSaw but they slice pretty quick(bandsaw), when compared to chain milling. Driving a 3/8's chain is much harder on a saw. So you need to do what you can to help it run cooler. If I was to mill with one I would use top quality oil at 40:1 like Stihl oil and set the high speed(when warmed up) rich just so it blubbers a little. If you stihl have the 3/4 limiters in I'd pull those out so you have full adjustment of your Hi/Lo speed screws. Also would do a muffler mod to help it breathe better too like this:
http://www.arboristsite.com/showthread.php?p=1504446#post1504446
There are lot's of oil threads and muffler mod threads/posts on this site if you do a search. Would like to see you get lot's of milling done and if you already know all of this then disregard and happy milling!
opcorn: