Does anyone know of an example of a head modification to a gas engine? The modified head that was created for the Thundertiger 1.2 makes a lot of sense when trying to alter the compression ratio. MVVS used to make a .61 engine that came with 2 heads one for glow and the other with a contra-piston for diesel (I have one around here somewhere I'll post a pic of). The diesel head had a two piece "button" design. That two piece head concept might be another way to change the combustion chamber for comression ratio.

I'm wondering if the RC boat guys have designed a bolt on head modification...anyone know?