I want more Hp for my 318

Actually on a 318 of this level headers only provide a couple HP improvement over stock manifolds. First I would check cranking compression, ignition timing, and jetting to make sure the engine is running as well as possible. If so then I'd recommend a cam change to a fast-ramp dual-pattern design like the Comp XE 256 or Lunati Voodoo 256/262. Either of these will raise torque all across the powerband and gain a LOT of HP at higher revs (probably at least 60, most likely 75).

What will really wake it up though is higher compression (new pistons) and better-flowing heads with big valves. Then you'd want to get some headers, and some better tires (ha ha).