Before you do anything with the injection pump you should check the timing. I use the drip tube method.It is more accurate.Some mechanics use other ways.The timing can be altered by loosening the three nuts on the front of the pump and the one on the bracket that supports the rear of the pump to the block.I'm not sure how much you can alter the timing. It depends on where the bolts are located in the slots.If you have have to remove the pump, you will have a lot of fun. Besides removing all fuel lines, you will have to remove the oil filter housing. You will really have fun doing that. I can send you instruction on how to time the injection pump(drip tube method), if you don't already have them.
Bill Lewallen