help with 69 engine build

[Longbedstepper]

Hi, somewhat stumped with my 69 k10 engine build. Engine is a 350 .060" over. 11:1 hyper pistons, trick flow 195 heads, heddman longtubes, edelbrock 1406 (600cfm) carb, and edelbrock performer intake. Cam is a mild summit cam. drive train is an sm465 trans with a centerfold clutch, and 4.11 rear gears. Truck runs smooth. Starts right up and has no hiccups running it through the rpm range. My problem is it feels like there should be alot more power. It pulls consistently but never really pulls like I imagined. I based my build from a hotrod article (they used stock heads not aluminum) and claimed in the 400 for horsepower And similar for low end torque. Would switching from the 1406 to a 650 double pumper, or 770 avenger really wake this thing up? It honestly does not feel THAT much more powerful then the old worn out engine that I pulled for a rebuild last year. Thanks for any input.