In defense of 484's valve events. It is nearly impossible to get one of the D&RGW's engines to run square in both forward and reverse. Over the years there have been many "hack" valve setting jobs done by the D&RGW that has resulted in eccentric cranks in the wrong position, eccentric rods and radius rods the wrong length, combining levers with the pin holes at different lengths (which messes up the valve lead), etc. In addition, the valve cages are not necessarily in the right spot, putting the port openings in the wrong places. Getting a 480 (or a 490) to run perfectly square in forward and reverse would be a major undertaking starting at ground zero and going from there. In the recent past some valve gear parts were "put to the print" which made things worse and the rest of the engine was not "to print". The only thing to do in the interim is to make the engine run decently square in forward motion in the "company notch" (2-4 notches from center) and get a good 1/8" of lead in the valve.