Opinions on the best value 2000 GMC 6.0L crate engine
 

To make a long story as short as possible, I bought a 2000 GMC 2500 with a 6.0L engine and have issues. When I bought the truck with 120,000 miles on it there was a rough idle. Returned it to the car lot after finding 1 cylinder low on compression. They had the heads removed and redone (I assume properly). When I got it back it ran smooth and seemed good so I was as happy as I could be at the time. After driving 80 to 100 miles the engine started smoking (blue, smells like oil) on start up. Thinking it might be a valve seal mested up when reassembling, I decided to drive it and see what cylinder the plug showed was burning oil. I have now put over 2000 miles on it and the spark plugs still look clean. It has used over 2 quarts of oil and now I can either see smoke or smell burning oil out the exhaust anytime it is running. So now I am thinking lower end issue. The truck has a rust free body and near perfect interior so I have decided to replace the engine and have a good truck. Any suggestions on a crate engine? I have priced NAPA (ATK reman.) and GM Goodwrench and there is a huge price difference but the same warranty. This is a second vehicle so milage warranty is not an issue. It has taken me over 4 months to put the 2,000 miles on it. Any ideas? Suggestions? Thanks

If this needs to be in another area, please move it. Thanks