have a 71 blazer with a 350ci.,4spd. edelbrock performer manifold and cam and headers with 3.73 rear. Also have an old beater for the ruff stuff The 71' does light off-road and a lot of street miles. Have an old rochester on it now from a 70' buick 455ci. I was considering either a holley street avenger (670cfm)or the edelbrock performer (600cfm #1406). Not doing any severe angles. Anyone have any comments on either carb?