cast iron or aluminum heads?

[mwilliams5891]

So I picked up a freshly rebuilt 327 short block yesterday and was turned on to some great heads by a friend on here and they have them in cast iron and aluminum. i'm not building a race truck but i'd like to get some good HP out of that little motor. so does anyone know how much more power ill get if i upgrade or if its worth it?

thanks a million guys


oh and if anyone knows where i could get a used tremec 5 speed for that 327 that would be great...also if anyone has advice about that 327 build up let me know