I just went through the Alton thing on my 74 a couple weeks ago. I bought the bike about 47 years ago. It had the stock points in there. At one time I upgraded to a Boyer and it performed well. Then I tried out a Trispark, I liked that ignition too. After that we were building my buddy's 71 and he decided to go with a Power Arc ignition from Old Britts. That thing was pretty awesome, his bike ran exceptionally. He said let's put one in your bike, I'll pay for it. I agreed, free is for me. I wasn't to happy with it, the 74 never ran as well as the 71. I think the timing was a little off. About 5 years ago I bought the Alton, I was still running the Power Arc. I wasn't too happy with the Alton, it had trouble spinning my motor. It was more like a kick assist. Looking back we think it may have been the shear pins failing due to the timing being out. I put the 74 in dry dock and rode my 30yo, dependable, Harley FXSTC. Due to time constraints of everyday life, we didn't get back to the Norton until this year. My buddy did a custom rewiring job, negative ground from the Grant Tiller website. Increased the cables from the battery to #6AWG, installed the old Trispark, installed 6 shear pins, and away we go. My buddy says now the Alton is now doing what it is supposed to do, spins the motor effortlessly. We also installed a rebuilt head done by @CarlH and I got some useful information from
@DennisMo in regard to the Alton. If you need shear pins contact Jack Manning from Classic Bike Experience in Essex Vermont, USA. He is an Alton distributor. $2.50 a pin. I bought 12. Grand total of $40 USD and that includes USPS priority shipping. Anyway

I hope to be riding soon, just got out of 2 months of rehab, and need to do some more. Not as bad as
@ashman, but I broke my right hip 3 months ago. Thank God I already had the Alton and it is working fine now.

If you don't limp, you ain't shit.