Excellent info YP, that's a lot of research you've put in. Thanks, although, still a little undecided on how we're going to attack the valve train.
The good news is that the crank from the front cut is a good one and will fit...see below

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The tale of two cranks.
By the way what do you guys do when you want to renew the rear crank oil seal? Even Ari is stumped by this one.
Rob, it turns out we are going overseas to have the piston made afterall (I think just to keep that truely international feel to the build!) This lot in Italy are going to make them
http://www.pistalracing.it They make a lot of pistons for Moto GP and World Superbikes, so hopefully they know what they're doing.
One other interesting discovery was made last week, when we went to a race clutch specialist and found that with only minor jiggery pokery a Triumph Dolomite Sprint clutch will do the job......so with the shaved flywheel and this little lightweight thing we're shedding the pounds where it counts (no jokes about my wallet please

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