Header headache may go to manifolds

[BobbyY]

I have a 360 LA in my 67 Dart with Headman super comps. I don't like the way they fit/hang down underneath. Been thinking about going to regular exhaust manifolds. The engine is north of 400 HP so it does need to be able to breathe. Does anyone know anything about these manifold numbers.
passenger side # 3870055 Driver side had stuff mounted in the way so I could not read it.
Also driver side 53009377 and passenger side 53009378

Any help appriciated

 

[1970Duster]

If using headers, Dougs or TTi are really your only bet when it comes to flow and fitment (besides custom made headers).