In looking at the data sheets for the Wico magneto, I was amazed to see that there were about 100 versions of the “A” series magneto, according to wico the magneto for the Howard Gem is the 955 and thinking about fitting the magneto to the “Gem” it made me wonder why they needed to make so many variations, as you can set the timing on a gem by slacking off the magneto drive on the camshaft to any position “Before Top Dead Centre” so the impulse will fire at any stage you want, I dont have a 955 magneto, so am fitting another model of the “A” series, does it matter? or am Imissing something obvious? PLONKER