I’ll post a strap to you tomorrow.
As regards pistons, can’t shortstroke pistons be turned down to fit any amount of wear in a longstroke bore ? And difference in compression height compensated for with eccentric little end bushes ?
P.S. I think that another issue is owners’ prejudice against 498cc engines. I suspect that there are more than a few 498 barrels sitting unused in sheds and garages, with plenty of wall thickness, that can be bored out to take turned down 596 pistons, giving a hybrid bore size around 550 cc. You would get a higher compression from the 498 head size, and thinner, lighter pistons as well ! Let us not forget that John Catchpole’s 100mph on very low octane ‘Pool’ petrol, was achieved on 498cc. When Arthur Breeze and Derrick Shire sprinted it the engine was around 648cc (from memory), and neither of them got to Catchpole’s speeds, and both tried exotic fuels. When I owned it I noted that the bottom sections of the cylinders were as thin as eggshells, and probably just as fragile. I never had the urge to sprint it after seeing that, and sold it to Pat Cravos after a couple of years.