If you have an F-series motor and want to gain 20-30 horsepower and gain 5-10 more torque without changing internal parts in the motor, Evolution Industries designed an adaptorplate to mount on a stock H22 manifold to the F-series head. A stock 1993 Honda Accord with a F22a motor was used to test the adaptorplate. Baseline pass showed 80.2hp and 117.4lbft at 6364rpm. After installing the adaptorplate with the H22 manifold it made 112.7hp and 130.0lbft at 6364rpm. So a gain of 32.4hp and 12.6lbft.