I hope there are still Norton fanatics following this post as I am a bit late in responding!
I rode Nortons both on the road and the race track in the 70's and 80's. The first thing I discovered was that the exhaust system is the most important part of the power plant. I learnt this when the baffle blew out of my Model 50 silencer and top speed went up by 10 mph! I subsequently discovered that Queens University Belfast did most of the design work on Dunstall exhaust systems ( I can recommend Dunstall Decibel silencers ) including the Norton factories 2 into 1 pipes with single short megaphone as used on the Formula Racer. I copied the latter and it worked very well on my racer, with both domi 88 and Commando 750 engines. It gave a wide power band and the 88 produced good power up to 7300 rpm in top gear. Use a poor exhaust system and you throw away all the good work done on the rest of the power plant.
If you use stock silencers check that a broom handle will go all the way through. If it doesn't, cut out the obstruction and be amazed at the difference it makes.
Getting back to camshafts, the stock 650 ss cam is good enough on a road bike. it was in the Commando which is basically a bored out 650 {with slightly bigger inlet valves) and in 1968 with 49 hp (60 hp was just marketing hype) was probably the quickest accelerating standard production motorcycle in the world. Always fit new cam followers when changing the cam.
Raising the compression ratio on the Norton engine also gives noticeably more power.
Incidentally I have, with thanks to the late great Doug Hele, a copy of the cam lift diagram of the factory '62 Domiracer produced by PD!
