With a conventional ignition system you want/need about 10kOhm max and 5 kOhm as a minimum to stabilize the spark. When you look at the scope with a 0Ohm ht system all looks spikey and not consistent.
But all adds up. From the coil to the plug. You can have copper core leads and a 5Kohm coil lead or 5 kOhm ht leads etc. etc. Bosch distributors have a 5Kohm resistor in them already and all plugs with an R in them like BPR6ES have a resistor in them also There are plugcaps with inbuild resistor.
It's just matching the parts you have. I had made at magnecor many years ago some sets that had plastic plugs with 5kOhm resistor that did fit inside the sprint tube that used the original top hat to look original. The leads were 0Ohm tinned copper core from magnecor without any white text. So totally original from the outside but modern plig caps with the resistance you want.
Jeroen
I did put some on my facebook site a while ago about this but it's in Dutch.
https://nl-nl.facebook.com/classickabel ... 9723457498
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