So….more header talk….this had me scratching my head

B3422w5 said
bearing in mind all those motors are stock stroke. 420 ish inch motor is a different animal from a 340

10 cid is a sneeze when the bore size is limited to near the same 4"-4.125" sizing.
Ime/o Builds can be worlds apart and THAT is more a reason imo for what it likes for exhaust.