Acco, yeah, the 392 sounds great! If you wanna drop it over here next weekend you could take the 345 out and swap 'em over for me, and I'll throw you a carton of Coopers. And since we're taking the motor out, might as well convert it to manual too. Make it two cartons? ;D
Seriously, much as it would be a great idea, I haven't the funds, equipment, knowledge or experience to be thinking about taking the motor out of this thing.
For that matter, if the 392 is that good, I wouldn't be taking bits off it; I'd be shrinkwrapping it and keeping it for a rainy day. Starting to sound to me like I need to find someone wrecking ex fire service Accos closer to home, I reckon the postie would struggle hauling a bloody great manifold on his little bike! ;D