WE have a 351C in our Cobra and have been very pleased with the track and street performance. The intake port plates help increase the intake air speed and the exhaust port plates help get the S*&^ out of he motor after the burn. We are at 9.9 to 1 and run 93 octane pump gas on the street. Ultradyne provided the bump stick which make this girl sound very bad.... Also go with the windage tray and coat all the lifter valley with glyptol. keeps your
oil from turning black after five minutes of running. We have a ball with the cleveland ....good reliable TORQUE and horsepower...I'm spoiled!