The saw tooth on the front of the heads makes them Vortec heads. Just for info, the intake manifold has a different bolt pattern then regular SBC intakes. If you remove the Torker II, make sure you purchase a vortec manifold. I have a stock intake that is virtually new sitting on the shelf. It came on my crate engine, if you are interested email me. The suggestion of the 600 cfm is right on. If however there is a high lift cam or other mods, it might not be enough. Hard to say without knowing what is inside.