Will 327 heads improve the HP of a 350 motor?

not really......you can have the 350 heads reworked for better performance. Besides, the 327 heads do not have the mounting holes for the alt. and other stuff that mounts to the front of the heads I tryed this on a race motor I built. The heads were just too small. ANSWER You can go to after market ex: Dart or whatever u want, have the cc you want for compression, valve size that u want ex: 202 intake, ported and polished. You will get top performance this way. Match the heads to the engine.