This is a quick synopsis:
The real ticket is the M47 crank with S52 piston shaved .71mm but using a 138mm rod. You might have to dish the piston depending on what compression you're looking for but it should put you around 11:1 without. This will give you 2068cc.
Or you can go S50 piston with same 138mm rod and shave off 2.65mm and dish it to whatever compression you'd like. This will give you 2045cc.
Crank nose needs to be turned down to fit crank gear and a second key needs to be cut. You can then go one step further and have the crank lightened as I did. The stock crank is 30lbs and the M47 crank is 35lbs.
Cheers,
~Ralph