Timing new injector pump on engine that was robbed of old pump...

Could use some help on this one... I know the best way would be to remove front cover and start from scratch.
  Is there a way to know for sure that the timing marks are lined up without doing so? I have read that the gears adjacent to the slot where the pump tooth lands are permanantly died, but I can't tell by looking at the cam gear from the top slot. I know the engine is off time because the kid I got the rig from told me he didn't bother to line the timing marks up before he robbed the old pump off it.
  I am a mechanic and I have some experience with these engines, but I always make sure I set myself up for the next step by doing things like lining up timing marks before I remove injector pumps...Just didn't know if there is a trick out there. I suppose I could fish around with a pick and find the Y on the cam gear. Hope there is an easier way ...COOP  

Got her figured out...Fished around with a pick and found a mark. Used a very reflective butter knife and with a flashlight verified that I in fact had the correct mark (Y)...Marked the adjacent teeth and now waithing for new pump to arrive...  

The Y on the injector pump face where. My problem was the same as yours. If I put motor at top dead center where does injector pump go. thanks derek