Headers might help, might not. I agree with Wildcat, try an Edelbrock 650. I think you'll see a significant difference from that double pumper. Make sure you have a good front end alignment and no overtightened wheel bearings or brakes dragging. Maximum tire pressure and larger diameter rear tires with a smaller width will help. Optimize your ignition timing and use a vacuum advance. Make your hood scoop fully functional. Buy a vacuum gauge and drive with one eye on it and the other on the road.
