In the 'Olden Days' of my youth we installed 10K ohm snap on resistors to the
plugs on MGAs, MGBs, TR3s and my trusty TR-4., They also worked on family
sedans, pickup trucks, and station wagons.

I don't know if such devices are currently manufactured. But, the Autolite web
page still lists resistor plugs. A 5K series resistance will work wonders for
spark plug noise.

If you have a DC generator as opposed to an alternator you will need to bypass
the high current connection at the generator with something like a 1 uF coaxial
capacitor.

These two engine noise suppression techniques should cover 90% of your engine
noise issues in the older vehicles.

/s/ DD, W1MCE [HF mobile for almost 50 years beginning with a 1953 Studebaker,
followed by a Renault dauphine, followed by the trusted TR-4, followed by babies
and station wagons.......]

- - -

Bob D. wrote:
I've had some luck reducing ignition noise on 2M in my MGB by putting a few
'clip-on' ferrites on the low tension side of the ignition circuit. (The
tachometer uses a current sense rather than a voltage sense, so the raw coil
current runs into the cockpit.)

Would ferrite also help on the spark plug wires? BTW, this is an old car
with points.