O.K. here's what I've found. 1. The Nissonger tach conversion does not like solid core wires, the RFI will make the needle flutter. 2. The Pertronix does not like solid core wires, they cause an intermittent misfire that will eventually cause the ingnition module to fail. I will now experiment with changing plug gap after tracing down My 2 issues.
Well first off :
Solid core wire in just about any application is subject to failure from vibration and is not recommended.
Automobile wiring harnesses and spark plug wires should use the stranded wire type
Radio Frequency Interference [ RFI ] in ignition systems can be controlled by:
1 Shielding of the ignition system and it's multiple stranded wiring.
Healey used this approach early in life ,kits could be ordered.
2 resistance type plug wires such as string impregnated with carbon
3 Spark plugs of the resistance type.Such as Bosch WR7DP
4 There is a special type. spark plug wire that contains a built in inductor.
This usually consists a special winding installed around the main conductors .
5 There are spark plug connectors that contain suppression. I use Bosh works a treat