Finishing the Boss 302 combustion chambers via CNC machine helps in several ways. The locating pad between the outer edges of the exhaust seats is eliminated, several areas around the chamber are unshrouded, and mainly, the chambers are consistent one to the other and accurately placed. In fact, half the intake flow gains are due to the chamber modifications, plus the more consistent chamber volumes mean more accurate and less invasive spark retard from the knock sensors. The compression ratio remains 11:1 because the basic Coyote/Boss combustion chamber is already at maximum brake torque. That means given pump gasoline it doesn’t respond to an increase in ignition timing or compression, and increasing either means decreasing the other to avoid detonation.