I decided to try the Street Dominator when I saw that it made almost as much hp in the Mopar Muscle intake shootout as the Victor. The Street Dominator actually made more hp then every manifold other then the Vivtor which it was close. But thats high end hp. I dont remember how it was in the midrange. Thats why I decided to try it. I can say we tried one on my sons Dart. He went 11.55 @ 116 with the RPM in the test and ran 11.59 @ 117 with the Street Dominator. SD had more mph but the RPM had the et as it was better down low. I would like to try an RPM on my 63 one day. Ron