What should the ohm reading range be for HT leads?

I have 8mm top gun leads.
I have problems with the ignition as one bank on the 253 will ping and the other won't, I had my multi meter on a ht lead to get the rpm and the timing light on #1 (900rpm), I then put the pickup on each lead and #2 cylinder read 1300rpm, then all the rest were 900rpm?? I have pulled the timing back to 4deg adv and it still runs rough. I did a comp test and all were 180-190 @ 10 revolutions, I have stripped the carby and cleaned out with the compressor and carb cleaner, fitted a new 82deg thermostat for winter, new fuel filter oil & oil filter, new spark plugs.....the dissy is an original converted to electronic (which i can,t buy a rotor for) had to buy a similar unit and replaced the brass arm, new dissy cap...what more can I do?

Will I need to replace the dissy itself? what type to use?

Help needed
Cheers
Darren