I would find the lowest mileage long block you can, 03-05 1500 or 03-08 2500, as none of these have MDS. You can always use an 06-08 1500or even LX engine, these just have the special MDS lifters and solenoids in them. Also keep in mind if you get a non 03 engine, 03's don't have EGR; from 04 on they do (simple to block off).