My SB build...

I'd run the factory 71 , 72 or early 73 (no EGR) intake with a TQ. Since your J heads are all but done cc'd and all , I'd run them. Run a cam you can use good valve seals and single springs. Run the vacuum advance distributor and a Chrome box and be done. Unfortunately headers are probably cheaper than stock manifolds, but I hate headers for a street car. You know what you are doing, it is decision time. Good Luck.