What kind of carb are you running? Holley or Edelbrock? There's a ton of variables that it could be. Start with simple stuff first; If it's low fuel flow, a simple thing to do is change the fuel filter. Since pulling the plugs doesn't show them being wet, it's not getting too much fuel. In keeping with the fuel issues, check the float levels in the carb too. If they're set too low they won't fill properly. If it runs like crap under 1/3 pedal, is it a constant pedal or a stomp of the pedal? In other words, does the car "buck and surge" at cruise but run smooth when you floor it? Does it stumble off idle or only at cruise? A cruise stumble could mean it's running lean or you have too much advance on the distributor at higher RPMs and can be remedied by turning the screw inside the vacuum advance to retard the timing. Give us some more info: how long has the car been sitting, what carburetor you have, engine rebuilt or just stock, what's already been replaced, etc. Hope that may start the diagnosis....

Cheers