the cast iron heads used on the B bodies (Caprice, Impala, Roadsmasher) are supposedly better flowing than the Camaro/Vette aluminum heads, and are identical to the Vortec heads everyone (including myself) has on their "old school" small blcks, but with reverse cooling for the LT1. that's not to say the aluminum heads aren't good, just that the iron heads are said to be better.
why not stick with the efi setup? when it's all said and done, you will have a bunch of money sunk into making it carbed, and only a little bit more $$$ and effort will allow you to keep the efi.
you don't plan sincerity.
you have to make it up on the spot.
wanna hear about 20 years ago when i was too smart to know any better?