No ECM, no smog devices, etc... just a SBC engine. Timing is 4 degrees. Changed the plug wires, cap, rotor, new plugs and the fuel filter. Hooked up a vacuum gauge and the readings are fine, no fluctuation with the needle readings, just a steady reading even when I raise the RPM's. Ideas? Stumbling in 2nd and 3rd gear when I take off or step on it. It smooths out once I get going. I can't think of any reason. Bad wires even though they are new?? Thanks!