I just installed a new Edelbrock dual plane intake manifold and an Edelbrock 1406 600 cfm carb on my '86 Chev K5 Blazer's 305 ci engine. I have adjusted the timing and idle mixture screws, and they are perfect. However, I have little to no power at road speed (20 mph and up). I've replaced all the vacuum hoses, installed a new factory style fuel pump, fuel line, fuel filter, new plugs, wires, and MSD distributor. I suspect there's still some adjustment on the carb to make, but I don't know what/where to start. I do NOT want to replace the metering rods or jets (these are brand new and sized for this engine - it makes no sense to replace them). Does anyone have any suggestion for me at this point? I'd greatly appreciate any help. 
