With my holly truck avenger on an older 350, I get an annoying idle miss fire with the idle screws 1/16" of a turn either direction from being perfectly bang on. I highly recommend a wideband O2 sensor with an A/F gauge, tuning a carb without one is a lost art, even going off of feel/RPM I was still way out until I used the gauge. going from a 10 to 13.5 mixture will give you almost 1/3 better fuel economy. The gauge will pay for itself x5 easily in fuel consumption and unnecessary stress after a few big trips. (Going from 5-8 mpg to almost 12).
It will also help diagnose future carb / engine problems including vacuum leaks, stuck chokes, clogged fuel filters, flooding, stumbles during power transitions (coasting to power), stumbles at 10-100% throttle, fine tuning the accelerator pumps and secondary's, backfires etc. https://www.amazon.ca/AEM-30-4110-UEGO-Ratio-Gauge/dp/B00N3VGPYS/ref=asc_df_B00N3VGPYS/?tag=googleshopc0c-20&linkCode=df0&hvadid=292977936168&hvpos=&hvnetw=g&hvrand=6573167427041104759&hvpone=&hvptwo=&hvqmt=&hvdev=c&hvdvcmdl=&hvlocint=&hvlocphy=9001313&hvtargid=pla-377903111462&psc=1
You need to be completely at 185F engine temp or hotter to accurately tune anything. Is this an electric choke or mechanical? you didn't mention this at all in your previous posts. If electrical, and it dies after 10 min it may not be opening causing a rich situation - possible electrical issue but incredibly easy to fix properly or just with a zip tie to troubleshoot. I doubt it is anything else electrical, as they really only need two hot wires to work - 12 volt ignition to the distributor and starter crank power, the rest are just accessories. It could also be the speed the choke is opening, possibly to soon? Adjusted by turning the black disk on the side clockwise or counterclockwise.
Timing is at 8....that's 8 degrees with no vac advance or total? Idle total advance, vac + mech should be in the 25-40* range, usually the more the better, I dont know offhand what a 360 and your cylinder heads like but in that range.
even if there is a huge vacuum leak, the miss should go away at WOT / zero vacuum.
Keep in mind;
Idle screws are idle af ratio
mid range power is primaries and the idle mixture together. Not just primaries.
WOT is idle mixture + primaries + secondary's. All three combined, plus the accelerator pumps if you really got on it.
A properly tuned 360 should be able to really test your AMC 20 2 piece axle strength on pavement if you still have that rear-end.
My services can be available with a complete holly jet kit, timing lights, vac gauges etc for a small fee
plus I cant even remember what a CJ7 is supposed to look like anymore. I have spent enough time and money tuning a carb I could have changed over to fuel injection now but that's another story.