Pork Loin

http://www.chowhound.com/post/45-lb-center-cut-boneless-pork-loin-roast-cook-661295?page=3
Pork Loin

The comment from "brooktroutchaser" was what I did. I had a 4.5 lb "half pork loin" (NOT tenderloin...those are like 2 inch diameter and the loin is like 5 inches diameter.)
"Pork loin roast: season with copious amounts of garlic pepper. Roast fat side up at 350 for 55 minutes. Let rest, lightly tented ten minutes. Slice thin."

I had it roasting on a rack and below it was butternut squash and potato cut into largish cubes (and tossed with oil and salt/pepper). It took an extra 30 minutes approximately to get to 145 degrees, probably because the squash/potatoes took some of the cooking heat. So if making it this way again I would budget 90 minutes time to finish cooking. Without the veges, I would try 55 minutes next time at 350 like the comment recommends. I also used garlic pepper that I had already and it turned out terrific. I didn't do any advanced prep, just seasoned it before putting it on the rack.