Your lucky I don't live anywhere near you. I'd be pushing building a hot rodded up Norton.
For example, you could build a healthy engine while waiting for those pistons to free up. Molnar (TGA.co.uk) has cases, barrels, and a quality crank. JS Motorsport has some nice rods and pistons as well as valve train parts. AN has bearings and chains and other small necessary parts. If that head is junk, talk to Matt at cNw about an STS head. You could also think about a belt clutch. Oops there goes that $10K budget I mentioned, and you'd still need buffing compound, and probably wheels, brakes and the list goes on. 
Save the soaking numbers matching cases for the next victim of Nortonitis. 
That said you could also do it all stock, but the Cobra would be teasing the Norton about being so vanilla.
Watch out for that Woodinville Bourbon. It's smooth.
I agree with johnm about keeping the revs down once you get whatever version of Norton you decide on put together. Unfortunately, if you build an engine like I am suggesting you will have a hard time not pushing the engine once in a while. Resistance is futile.
