Wow, did not expect so much interest. Here are some build details and pics.

The go faster bits I have pics for: A Nourish crank is machined out of a single forged billet of Unobtanium and will not flex. [1] Here it is .

Carrillo rods & Cosworth pistons, [2] these are out of another engine  but are identical.

For all Meriden Bonnies, to get the power out without destroying the engine you need to fit a much bigger crankshaft main bearing on the drive side. Like a Timken double roller. So you need to machine out the crankcase bearing housing and fit a steel insert. [3] Like this on the inside . The flat top stops it rotating, the csk fixings stop it migrating inward and closing up the end float. It's CNC machined for accuracy and is an interference fit in the crankcase.

On the outside, the crankcase is welded up and machined back to accomodate the wider bearing housing. You need a coded welder to do this, not your mate down the road. The alloy plate is an oil seal housing otherwise the engine oil will migrate through the double roller bearing into the primary. Small fixings are fine as it takes no load.[4] Should look like this when you're finished .

[5] Getting things to fit part 1 , have a look in daylight.

[6] Oil tank and battery box 

[7] Carbs fit too, that's handy 

[8] Dry build, red marker means 'needs attention' 

[9] Always another job on the list