1600cc – was a 69mm crank with 85.5mm pistons and cylinders – we don’t supply these because the “1700” 87mm size fits just fine with the heads without needing modifications. Gives more power.

“1700”cc – (actually 1641cc) – 69mm crank and 87mm pistons and cylinders

1835cc – 69mm crank and 92mm pistons and cylinders requires modifications to the heads to accept the larger cylinders. Also requires liquid, high temp gasket. There is less material on the heads though so you need to be more vigilant about keeping the dust off your engine so it cools.

NEW 1759cc engine has a longer crank stroke for more low-end torque. 87mm pistons and cylinders have more material for better cooling.
We also put 1.25:1 ratio rocker on the new engines for best valve function.