AMR of Tuscon sells a lot of Norton stuff, but I can't vouch for their work. Maybe someone else can. If you need a mechanic, Delores, CO, Colorado Norton Works will do you right for a good price. Phil at Fair Spares in San Jose is a good guy. There's a guy in LA too forget his name, he's got a shop. Rabers near SF, Old Brits in WA, but he's backed up 6 mos. You're in the wrong part of the country for me, but there's no one around my area I'd trust except Leo Geoff in Memphis. Couple of guys here on the forum, Windy in TN, I think. A fellow in TX.
Personally I'd do it myself, but then I've done it, the full monty. Believe me they're not that hard, I did it in a spare bedroom and I don't have a mechanics shop, not even a drill press and mine's running perfectly as far as I can tell. But then I love fettling with all the things I need to do. My clutch pivot screw was messing up today and really affected the clutch, and when I got home, it was a piece of cake. It's something you need to do with these bikes, especially the early ones.
I'm sure someone else will pipe up.
Dave
69S