Sanderson headers makes block huggers for the big block. I have often thought of going that way instead of stock manifolds.

http://www.sandersonheaders.com/Sanderson-DD2-Chrysler-383-440-V8-Blockhugger-Header-Set.html

11.67@118 1.88 60' with only 7-8 lbs of boost. Turbocharged, megasquirted, 407 BB, 440 source heads, roller cam, 9:1 comp. http://s292.photobucket.com/albums/mm14/beansgracie