I am in the process of selecting a different cam for my .30 over 312. Stock pistons, ballanced, E carbs and intake with the manifold port matched to the heads and the gasket. Plan on adding Mummerts Aluminium heads at the same time. Currently have a Crane cam from the late '60's and want newer technology. Will be running close ratio toploader 4 speed and 3.89 gear for the street and 4.11 or 4.56 rear end for the strip. Looking for shifting it in the 6000 to 6500 rpm range. Have had the existing set up to 7000 rpm but power falls off and no use pushing it to 7000 rpm. I am looking at the Isky F300, Mummerts  Y292S, Y280I-11, and Y284S. Looking for opinions and what is everyone else using?