In my book high idle is to be set at 2520-2640, low idle is 1150-1250 and the timing is 19 degres BTDC........ I have also seen the crankshaft dampner "shift" "slide" on it's rubber element so that the timing marks are in the wrong place, i think I lost a few nights sleep over it after doing an overhaul and we couldn't get it to even start, I rechecked the timing about ten times, pulled injectors, pulled valve cover and watch the valves move and the fuel spill from the injector line, I was about to the end of my rope and somehow we noticed a difference in the inside part of the dampner and the pully part, $500.00 later (installed new dampner) and reset the timing and poof she ran like a scalded dog.