The combustion chambers were whittled down to a mere 27cc. That is not a misprint; we said 27cc. As mentioned, the rest of the chamber was crafted into the piston top, so the heads were able to use a minimal chamber depth and completely unshroud the valves when opened. Intake port volume is a zippy 290cc, which is small enough to promote great velocity. The heads wore valve covers crafted by Unique Aluminum Products.