You should start by looking at the cam recommendations for operating range. The Comp 270H (224@.050)says it's range is 1800-5800 RPM, and suggests a 2000+RPM converter. The Comp 280H(230@.050)cams range is 2000-6000 RPM, and suggests a 2500+RPM converter. But converter companies suggest to select a converter that is at an RPM lower than your engines RPM at 65 MPH. So these suggestions may help narrow down the choices you will need to make.
