Limits of an Edelbrock performer and 1405 600cfm carb

The intake and carb are not the "choke point" unless the cam, heads and exhaust have been upgraded and modified. Just think of an engine for what it really is, an airpump. Look at the carb, intake, heads, exhaust as a funnel. Where ever the flow is restricted is where the funnel narrows down. Improve one are and the funnel narrows somewhere else. That is why just replacing the carb and intake manifold doesn't really open up the engines flow/power until you improve the cam, head valve size,port work, exhaust headers etc. Edelbrock sells a top end kit which does just that. Just add headers.