65 barracuda with 340.. What heads? What Headers?

Iron heads with 2.02 valves, setup right and around 10:1 compression is usually good for 350-400 horse. Depending of course on cam choice, dynamic compression. etc etc. You can go aluminum heads, but if you're looking for on the cheap iron is always a safe bet. For most power the best headers are long tube, 1-5/8 primaries with the power you want too make. You can run block huggers or shortys, but you will give up some power to do so. As a tip I'd get them cerakoted. That's always good for 20-30 degree's under the hood.