My electronics date back to tubes. So I'll probably bug you guys a lot.
Never fear. I started my electronics learnin' dragging an old tube type TV home from the dump and making it work. Dad was so impressed I got to keep the old console in my room. I've got a Heathkit ignition scope that I still use for ignition system diagnosis. I think we can help.

According to GM AKAH is for 1/2 and 3/4 ton vans with 5.7 V8 and 700R4 transmission. A factory calibration for a G van with 5.7 and THM400 can be found here.