HD Engine Tuning

Over the years I have tuning my HD engine in my C-30 a number of times with reasonable results.
A few months ago I overhauled the carburetor and decided to invest in a air fuel ratio meter to assist with setting up the carb once it was back on the engine. The results were amazing. A few weeks ago I returned from a 2300 Km trip. The engine did not use any oil and the oil remain clean. I have attached a few pictures of the spark plugs which were cleaned when the carb was done. Never seen the plugs look so good.
I have also attached a picture of the Pertronix unit I have had under the distributor cap for the last 15 years which also does a great job in keeping the engine run nice and smooth.

When I was in High School, I tuned my R-110 by ear and thought I did a good job. Fast forward a million years and last fall I tuned my D-2 by ear just as I used to, then did as you did late this winter and picked up an air fuel ratio meter - what a difference! Either my hearing is completely shot now or I was never that close to begin with, but initially my readings were in the 15-16 range before I got things dialed in according to the meter. The D-2 is running better than it ever has now, just like your C-30

Your C-30 is a gorgeous truck, BTW