Just that, a gyro in the air. For the big bore, have you considered using RC8 105mm pistons? I'm looking for one myself to do some measurements, that would be an easy bigbore than. I think getting a piston wil be either the hardest, or the most expensive for a bigbore block. The piston pin is the same, rods diffrent, stroke about the same so the pin offset should be exactly what we want. No idea about heights though. I'd love to build my 999cc in to a 1180 here!