Can you have too much header?

[westie47]

I’ve been looking for TTI headers for my 440 but they are back ordered til late August. The only one’s available are 2” primaries with 3.5” collectors. I was looking for 1 7/8” primaries. Are 2” primaries too big? My engine is 450 hp/528 lb-ft with 2.5” exhaust.

 

[33 IMP]

No.

 

[33 IMP]

I have two inch adjustable hookers on my 500 hp 440, and a 3 1/2 exhaust. Not a problem. IF it's too big, you won't know by the seat of your pants. Also have two inch headers on my small block, also with 3 1/2 pipes. Runs just fine.

 

[Rusty knuckles]

First post nails it.

 

[WileERobby]

Absolutely not. Breathe, baby, breathe.

 

[33 IMP]

I have seen dyno tests of headers where the last one was "too big". The power and torque loss was insignificant compared to a "too small " header. And the ones that were "too big" were MONSTROUS. (2 3/8). 2 inch are not monstrous.

 

[sam dupont]

"Too much is always better than not enough"
Bob Dobbs, Church of the Subgenius

 

[INTMD8]

I think most headers are bigger than ideal.

With proper port alignment/flanges/attention to tube angle/radius I think most could be much smaller than what's commonly available.

Bigger than necessary isn't going to kill any high rpm/max hp but I think if-properly- sized, could contribute to the power curve below peak power while making the same peak.

- That while resulting in more spark plug/plug wire clearance and ground clearance.

For your power level and exhaust system I would be more inclined to go with even 1 3/4 primary over 2".

JMO

 

[Kern Dog]

I've read that in most cases, the header tube diameter needs to be close to the exhaust valve diameter.

 

[Splangj]

Interesting thread! I’ve been running 1-7/8 on my different BBs for decades. I’ve read every test I could ever find. The real horsepower lost is probably the extreme up to down angle from the ports to the header. That’s the header style I have, and its way better than a manifold. True racers get fender well headers to keep the flow going up from the port. nevertheless, I’ve read 1-3/4 are good to around 450hp,1-7/8 around 575. Just what I’ve read. But stepped primaries are pretty nice…..

 

[Splangj]

Didn’t mean real racers in last post. Should have said serious effort cars or the like. Just don’t want to get hammered to death over that….