FL,
Just passing along what I was told when building my 383 Stroker for my 46; the builder is a local race engine builder. I had him put my heads on and cam in and then break it all in. I chose the parts for low end torque since I have a 3:08 rear with a TH400. While picking up the engine, I asked if my stock GM "rams horns" would do OK with this 383 with aluminum heads. Builder told me what Hot Rod Lincoln posted above. I will never reach the RPMs needed to gain any benefit from headers. With all the heat related issues that sometimes come along with headers, he advised me AGAINST using headers for FOR using the cast rams horns. I don't have any advice in regard to cast exhaust for your BBC...but just passing along what I was told. Other tidbits I have been told; some of the cast parts flow pretty good anyway. Good luck and have fun with your project. Either way you go it should have some pep.
