Hey Bob K & anyone else
It seems like I remember you going through something similar to this about a month ago, and I wanted to see what you came up with. I have finally completely de-emissioned my 258 by finishing the nutter bypass last week. I am still running the Carter, but the stepper motor needles are seated and it is unplugged. I also chose to keep the manifold vacuum for the vacuum advance because it is so much stronger than ported vacuum (about 14" vs. 1"--right off idle). Anyway, the jeep is running great and I'm getting about 15-16 mpg, but the amount of timing that I can now set it to is quite high relative to stock. I know stock is about 9 deg. at 1600, but when I put mine at 8-deg at idle (which is 16-deg at 1500 rpm), I still could not get it to ping even when flooring it, so I bumped it up to 10-deg at idle, which is about 17(!) at 1500 and it only pings when I really stomp it in 5th gear with the AC on (this is with 89 octane gas). Therefore, I'm inclined to leave it there because I seldomly ride it that hard, and just wondered if your results were this far from stock.
Currently an '86 CJ-7 and a '77 CJ-7 Golden Eagle---#4 and 5 following a '01 Sahara, '90 Sahara, and '85 CJ-7....