Header size ?

Is there such a thing as header size to big ? say 2" versus 2 1/2 " ?

depends what its on

richter69 wrote:depends what its on

466

i cant see where it would need a 2.5

richter69 wrote:i cant see where it would need a 2.5

I don't think it would need them either, but was wanting to know if it would hurt power and torque to run a larger primary tube header ?

I would think 2.5" exh. would hurt torque down low on a 4.390 bore 466.

on a n/a setup i'd think too big would hurt torque but how big is too big? i was looking at 2 3/8 for the 605 but 2 3/8 to 2 1/2 was what i got. dynatec was one place i looked for info.........

whitefield wrote:Is there such a thing as header size to big ? say 2" versus 2 1/2 " ?

Yes there is. It's been proven countless times on dynos everywhere. Chapters in books have been devoted to the subject.

Charlie

c.evans wrote:

whitefield wrote:Is there such a thing as header size to big ? say 2" versus 2 1/2 " ?

Yes there is. It's been proven countless times on dynos everywhere. Chapters in books have been devoted to the subject.


Charlie

Thanks for the info.

You will lose exhaust velocity which will hurt during the overlap period when your starting your intake charge. (which hurts torque)

Unless it's a over the top 466, 2 inch is all that will be necessary.

IDT-572 wrote:You will lose exhaust velocity which will hurt during the overlap period when your starting your intake charge. (which hurts torque)

Unless it's a over the top 466, 2 inch is all that will be necessary.

I got to thinking what if you are running a 390 to 427 cubic inch engine would going from 1 3/4" to 2" primary headers be to large ?

fwiw we run a 1 7/8 on our 306

richter69 wrote:fwiw we run a 1 7/8 on our 306

Again, its about application. 6000 converter on a 306 sure, not a problem, but I would be willing to bet it would be just as fast with short tube 1.750 primary's on it.

whitefield wrote:

IDT-572 wrote:You will lose exhaust velocity which will hurt during the overlap period when your starting your intake charge. (which hurts torque)

Unless it's a over the top 466, 2 inch is all that will be necessary.

I got to thinking what if you are running a 390 to 427 cubic inch engine would going from 1 3/4" to 2" primary headers be to large ?

If it's a full out race engine, no 2 inch will work. That's what I ran on the 414 Windsor with c-302 B's 6200 rpm converter. Shifting at 7200

IDT-572 wrote:

whitefield wrote:

IDT-572 wrote:You will lose exhaust velocity which will hurt during the overlap period when your starting your intake charge. (which hurts torque)

Unless it's a over the top 466, 2 inch is all that will be necessary.

I got to thinking what if you are running a 390 to 427 cubic inch engine would going from 1 3/4" to 2" primary headers be to large ?

If it's a full out race engine, no 2 inch will work. That's what I ran on the 414 Windsor with c-302 B's 6200 rpm converter. Shifting at 7200

Thanks, I think I am understanding this header deal better!