Easy way is call one of the many builders here Todd at Marsh Perf will put you dead on his Sidewinder heads are better than others in that price range and all you need--he can also put you on the rest of the combo--500HP is THE MAGIC number that 90% of all engine customers request for some reason 100 different ways to get there but with those heads and correct cheap flat tappet cam and then add in a set of the new Wiseco Street Protru pistons ( less than $425 with rings --lite and forged and awesome for a street build) add some PRW stainless rockers for cheap reliable performance in that category--pick your intake--I love the Performer RPM but it can be a pain with drop base thin air cleaner needed so the Holley Street Dominator still available new is low and makes killer street intake cheapo headers any 750 carb you can locate and Bam! ya gots 500 HP that will melt tires and be tons of fun