Depends......most of the aftermarket leads use copper or tinned copper stranded wire inside a 7mm insulated cover..so the leads themselves have very little resistance. It's the plug caps and sometimes the connectors that carry the resistor, these are usually 5kΩ (5 Kilo-Ohm) (ends often 1kΩ) but these normally have the resistance value printed on them somewhere.
There is a possibility that you may have the much less reliable 'carbon impregnated string' type.....the resistance is in the lead itself and varies depending upon it's length....(often called 'performance' silicon but god knows why)
This HT lead typically has a resistance of 3,000 to 20,000 ohms per ft. depending on the manufacturer.
Are you dropping on to 3 cylinders? do your plug caps have shiny metal shrouds? if yes then use a pair of side cutters and remove the shrouds.
I made up my own leads using the existing ends and new lead and plug caps..this is what I used to make mine...Lucas Hypalon (quality)
http://www.ebay.co.uk/itm/7mm-HT-Igniti ... 33759b45a2" onclick="window.open(this.href);return false;
If your leads are already 'Copper core' then another option would be to just replace the plug caps themselves....I used 4 of these:
http://www.ebay.co.uk/itm/1x-NGK-Resist ... 3374f7d1f4" onclick="window.open(this.href);return false;
Martin
