383 + 71 Demon = what parts fit?

I bought a running 68 2bbl 383 or $175 today and plan to clean/refresh it with a few goodies as well as backed by a 727 - going in my 71 slant 6 Demon.. what parts fit what don't? It's a no option car so no power accessories..

I know the B body Hedman Headers are said to fit and I plan on Trans-Dapt swap mounts but do they really work?

Plans are a small cam, re-gasket with thinner HG's to bump compresion, dual plane 4bbl intake, stock converter an trans w/ a shift kit, 3.23 gears in 8 3/4