Is the 340 internally balanced? The 360 is probably externally balance. Is the flywheel the same or do you need a different one like the flexplates. I have no idea but you should make sure your 340 flywheel is compatible.
The Cast Crank 340's (generally '72's and deffo '73's.) and 360's are both externally balanced. Cheers, though. :) Its things like this that would catch me out. :)
