With you currently having the 383, personally the only way I'd go would be to rebuild that baby and that would cost you the least amount of $$$$ and be the simpilist to reinstall, I'd recomend replacing the stock manifolds with the high performance factory manifolds, much better flow, and forget about headers, the e-bods are a pain when it comes to b/b-headers combo. You already have a big block set up, why change it? Unless................you went with say a 440 or a hemi?, lol.