Do i need bigger heads on my 318?

318's don't need bigger heads or valves for that matter unless you are going to look for high rpm use only. if it is a dalily driver w/ very limited upper rpm range 5600+ than keep the 318 stock heads and install larger exhaust valves. look to the many threads on here for further info. bjr is the 318-360 expert here. he can set you in the right direction. if you over cam it the car will lay down on the bottom end and do little to impress you. look for a cam that fits your intended use. comp cams xe 256 is a great daily driver cam. step it up to a xe 262 for the next level. your gearing, carb, and many other factors will determin this....so in a nut shell if it is a basic daily driver comp cams xe 256, stock heads with good valve job will do fine!