906 Heads?

youre good to go buddy... all Mopar big blocks (low-deck "B" motors like the 383 and raised deck "RB" motors like the 440) ALL use the same heads and can be interchanged without modification because the difference is in the intake manifolds, not the heads.

So as long as you stick with the correct intake manifold for your block, its easy peasy bud.
here are some pretty cool Big Block Mopar cylinder head articles written by the great Steve Dulcich if you havent already read them... really good stuff and may even change your mind on those long coveted 906s!!!!!

"Mopar Cylinder Heads" Part 1
http://www.hotrod.com/how-to/engine/5115-cylinder-heads/

"Mopar Cylinder Heads" Part 2
http://www.hotrod.com/how-to/engine/5118-cylinder-heads-ii/