This kit features a 7mm stroked crankshaft with 3mm shorter rods.
This combination results in a piston deck height of + .5mm (using any size pistons available for the RE Twin) and requires crankcase and balancer shaft clearancing.
With stock pistons, displacement is 715cc at 10.7:1 compression.
With S&S 750 kit (83.5mm bore) displacement is 820cc at 11.9:1 compression
With S&S 865 kit (90mm bore) displacement is 951cc at 13.6:1 compression
Cutting valve releif pockets in the pistons is (almost certainly) required and reduction of the piston crown to bring the deck height back to 0 is recommended.
Decking the pistons and enlarging the valve releif notches results in lower static compression ratios.
With .5mm decked stock pistons, displacement is 715cc at 10.0:1 compression.
With .5mm decked S&S 750 kit (83.5mm bore) displacement is 820cc at 11.2:1 compression
With .5mm decked S&S 865 kit (90mm bore) displacement is 951cc at 12.6:1 compression
Kits are balanced to 50% for S&S 90mm pistons and can be used with or without the counterbalance shaft.