I'm in the process of removing injector pump from a blown motor. I can't get the motor to turn to get pump to TDC before pulling the gear. What are my options if I pull it as it sets, which is about 90° out. I assume TDC is for timing of the pump. If the pump is reinstalled on a working engine, would I install it the way it came off, 90° out, or is there a way to time pump to TDC once it is removed.

You do that so you dont drop the shaft key into gears on a good motor. Timing is set by the key  and the pump gear. It makes no differnce timing wise on what orientation the pump key is. It is mainly for ease of instalation. I pulled my last mistakenly at about 80* off of TDC. I did rotate the motor for reinstall. Pulling the timing cover is a lot of extra work.

If you are using the pump on another motor you need the key. They are pump specific for timimg reasons. If it does drop into the old engine you can buy another. The keys are numbered and the key # should be on the pump data plate.

ⁿThank you dripley. 

Thank you dripley and the key has a small arrow stamped on top. That arrow has to be pointing the correct way, but I cannot remember if toward the VP or the gearcase. Some guys use a drop of white out paint on the key so they can see if it's lined up with the gear. That's looking from the front while installing. 

You are right about the arrow. I think it points to the front. Think that is in the install article.