Another thing that needs to be addressed is, If he will be running the factory pistons, Going with Aluminum heads the compression should be raised a good full point to compensate, so theres another exspence unless he mills the Aluminum heads. IMO it isn't worth it, The RHSs flow just as good or very close as the Eddys OOTB between the both.

75 Duster, 451 10.87 @ 123.58 NA 97 Z28 6sp., 12.01 @ 115 on a 100 shot 71 Swinger. 360 magnum. 12.58 @ 105 78 cutlass, 469 BBC. 12.70 @ 108 on street tires. http://www.youtube.com/watch?v=Z2kqNmMfheU