I tarted my last A10 up to rocket plus spec 9.5 /1 piston, 357 cam, Alloy head, Goldie silencers and so on, then called it a Rocket Gold Flash.
Then found it was a pig to start, tried various ignition and carb settings to some but not a lot of betterment, when it did start ( had to be within three or four kicks or the plugs fouled) then it pinked on hills worryingly, Pinking and starting were improved massively with Pazon electronic ignition and 8.5 / 1 pistons, it is now a good ride and was a pleasurable and interesting exercise.
With hindsight, I now prefer a more standard Flash and intend to bring it back to that in the future as I do not use the extra oomph that it has but still do not regret the experience and knowledge gained.
One thing the bike has are down tubes cut and shut, probably means it has a lower sell on value but it turns quicker and more confidently than my other Flash.
We are fortunate that spares are available still that allow builds to personal taste (and back if required)