Truck Repair: M11 timing, woodruff key, valve train

Question
QUESTION: running overhead on M11 that previous tech screwed up accessory drive timing marks in relation to setting overhead. How do I get back to square one?

ANSWER: Can the motor still roll over by hand or does it get stuck. If your on A with cylinder #1 are valves loose or tight. What are #6 valves like on A #1 just trying to get a better idea where to go to. I've had a similar experience on a isx by accident but I caught my mistake when I adjusted the wrong cylinder I couldn't roll the engine to the next setting because the wrong adjustment would bottom out in the valve train and not let the cam roll over the hump. In that case I backed it up to the previous mark I adjusted and backed off the valves and injector and started from the beginning again to cover myself. If you can give me some more details how things feel I can be of some more help to you.

---------- FOLLOW-UP ----------

QUESTION: well, it felt as if number 1 was ready, as both valves were closed and number 6 exhaust was tight. I was on A, and as I set intake/exhaust then Injector to proper setting, went to roll engine and it was stuck to the point that I knew something was wrong. previous tech replace accessory drive, but I don't think timing was taken into consideration. Not really sure if my A, B, C marks are correct. I am aware of the viewing hole on the front cover to check cam marks, but not really sure about how to correct this mess. Sorry for the delay in response, left for dinner. back on it now.

Answer
Well definitely would start by backing those settings off on #1 that you made. then I would check that the timing marks through the front view hole are right. then you should be able to proceed with running the overhead like you were. the only way that a,b,c can be off is if the timing marks on the gears are off the front pulley has a woodruff key on it so it can only be put on one way unless that woodruff key was left out. Now if he didn't set the time on those gears and you back off #1 and it still feels like its getting stuck when you roll it I would probably loosen the bolts on your rocker shaft hold downs so you can get that timing right.