Concerning the left side arm on the IP that goes down to the advance/retard plunger. I turned the screw on the end one half turn out so the plunger didn't go in so deep. I also replaced intake valve seals. Now I pulled a load and can start reporting.
Starting up has a louder rap but that quiets down when the cold advance drops out. It seems to be faster revving to 3K.
Pulling 24,000 GCVW it has a little better pickup. Cruising at 55 mph, 2500 to 2600 RPM, it seems to have a little more reserve power on a slight hill, although it still caves in on a steeper hill. It has less retard factor when I bury the pedal but it is still suceptible to it. It does seem a little more aggressive.
The exhaust is now nice and clean pulling on a hill, although starting out on a hill I noticed black smoke. Oil consumption is a little better (new valve seals), now about 1 qt for 250 miles. Still about 10 mpg and no change in operating temperature.
I'd say less retard plunger helped the truck. To the point where I'm satisfied (I only run 55 mph anyway) No more thoughts of a three speed auxilliary, this will work as is.
Thanks for the discussion that made this possible!
Be advised it is fairly risky to play with anything on the injection pump without an EGT gauge. You may be running a bit advanced now which will result in higher EGT's. You can get a real good one HERE.
Install time for a clamp on probe style kit is less then an hour.