Timing question

[backfromthedead]

My shoulda-been parted out truck has a weird issue. If I set the pump to the stock timing marks, it just blows white smoke, and wont hit a lick. If I push it to the head, it runs, but only gets 12-13 mpg. I pulled the timing cover, and the gears were lined up correctly. I suspected that the pump was a tooth back from the previous owner thinking he was advancing it, but that wasn't the case. It's a 93 w-250 auto, with 3.54 gears. Stock as far as I can tell. Should I jump one tooth and move on, or should I be digging deeper. First time playing with these engines, kinda confused as to why its doing whats its doing.

[spencerdiesel]

If it runs acceptably w/ pump to the head but is worse the more you retard it, try more advance. Advance a tooth, retard the pump and advance from there. See what it does.

What letters are lined up on the gears currently?

[backfromthedead]

I lined up c on the cam gear mark. I didn't touch the pump yet but it fired instantly, and ran smoother than it ever has. It's definitely on the right track, I just don't understand why factory correct wouldn't even start. I debated on bumping two teeth given the situation, but stayed conservative until i figure out whats going on.

[backfromthedead]

As it sits, it is to the head, and 1 tooth advanced.

[DodgeFreak]

The pump key wasn't mushroomed in the gear was it?

[backfromthedead]

It has seen better days, but it still had the right shape. Cummins was closed when I went up there today, i had planned on getting that among other things. It didn't give me any grief and the gear lined up like it should have, similar to a Briggs flywheel or something like that.