Yes Nev the block, crank and cam have all be crack tested including all in the gearbox The crank has been welded to take the extra hp, the cam has been totally reground to ensire corrent profile so that the lifters rotate and the gearbox is exactly the same that is used on the 914 engine so it will take the power. The lifters not rotating has been a issue for the Rotax and this has been the source of cam failures in Rotax, The big thing for the gearbox is the weight of the prop and extension and spinner. Mine is only 2.4kg total and extremely balanced so gearbox load and wear will only be by the physical hp applied to it. The main bearings in the gearbox are now SKF and not Fagg the SKF is a better bearing