2005 QC Unported Street-Strikers, Unported Intake, Headers, etc. 226/228 on a 115 11:1 on pump gas 600.3/598.2 Dynojet through the auto and cats. I think it was 387 when I bought it brand new in 2005 600.3 divided by 505 cubic inch= 1.18 hp per cubic inch through the auto. Or 1.23 hp per cubic inch IF it was through a standard... But it isn't. Past couple of tanks 19 Imperial miles per gallon. So the engine seems to be efficient. Im happy with that.