Header question

[A05C]

Im trying to figure out which headers i'll need to go with for my application.

Im building a RHS headed 408W with an auto.

my question is, which headers will i need to go with. there's 2 sets of bolt holes on each port

http://www.racingheadservice.com/Base/Images/Products/IRON_ASSEMBLED_SBF_400.jpg

Any help will be great
Thanks,
Andrew

[2Kblacksleeper]

I will take a stab at this and say that one set is for the standard 2.5" and the other is for the larger3.5" bolt pattern headers.

I know the Dart Pro 1 cnc heads have to have the 3.5" pattern.
I hope this helps?

John

[Jeff88coupe]

I would go with a wide bolt pattern flange header...at least 1 3/4" if it's going to be more of a milder street 408. If you have the $ go with a 1 7/8" set. I think Hooker,accufab,kooks all make ones with the wide bolt pattern flange. Mac might even make a set in 1 3/4".