I'm about to buy 1 and I thought this was basically the 4-1 2.5 inch collector now after searching i'm not so sure and can't find the exact specs for it.

Can someone help me please??

 

its a 4-2-1 design...similar to a gs-r header, only longer (obviously) its a good, stock header, but other then that wont make much over a stock b16 header. there is no proof on this, but ide just go with a stock LS header, and move the flange...the butt dyno was telling me that the LS OEM header was makign more power then the dc 4-1(us spec)<<<that thing is a piece of junk. if you are going to buy a header dont be cheap. i went with a comptech race header (retail is about 1200) but made a TON of power over even the dc jdm 4-1 plus my exhuast sound gnarly

 

I think you mean the USDM Type-R Integra Header.

The original USDM (and EUDM) Header is a 4-2-1 Design and is not 2.5'' (i think it's 2'').
I would buy a Header that fits exactly (without adaptations) instead the original Header.

---> I buy a Comptech 4-2-1 Header and are very happy with him.

here the original Header:

... and here the Comptech to compare:






greetz
sven


Modified by Mr. Svonda at 6:59 PM 6/27/2005

 

Yummy

 

first pic is a 4-1 JDM header.
second pic is a USDM exhaust manifold.


As for Specs... If you looked in the FAQs you would have found this: https://honda-tech.com/zerothread?id=274617