Today I removed the injection pump. Man, what a job that is.
Sure enough, the timing mark on the pump was a good 1/4" or more "retarded" from where it was supposed to be, with #1 cylinder at 20 degrees ATDC on the firing stroke.
I reset the pump and installed it.
Then I rotated the engine about 1/4 turn backward....and then came forward to TDC for #1. I loosened the cinch clamp for the distributor, and pulled the distributor completely out. Then I used a magnet up pull up the distributor drive gear and re-clock it one gear tooth in the clock-wise direction. I set the distributor back in, gave it a rough adjustment and the engine fired right up.
I did a quick setting of the mixture, idle and timing, and the engine runs great. The headgasket is retorqued and tomorrow I'll take it for a short drive and then come home and dial in the mixture, linkage, timing, and idle.
Too bad I didn't do this right the first time eh?