Header tube size
Thread Starter
Le Mans Master
Joined: Jul 1999
Posts: 5,005
Likes: 38
From: jackson nj
Header tube size
I've been told different things recently by both Vendors and end users, but cannot get an answer from manufacturers....yet. What I'm trying to confirm is this, how do you verify the header tube size? I have been told it's the O.D. of the tube and also told it's the I.D. of the tube. I have always been using the understanding that the measurement is the tube I.D.. What have others been told??
Instructor
Joined: Jul 2015
Posts: 239
Likes: 49
From: Pittsburgh PA
I am guessing it is on the ID of the tube. this is based on each manufacturer may use different thicknesses of material and coatings but in the end the ID should be the same right. Thats what makes the most sense to me.....but in the end its just .02
Safety Car
Joined: Aug 2000
Posts: 3,711
Likes: 43
From: San Antonio TX
Tube is always OD. Headers are made of tube.
Edit: Here's a link to clarify it beyond doubt: http://www.atc-mechanical.com/tube-p...size-overview/
Edit: Here's a link to clarify it beyond doubt: http://www.atc-mechanical.com/tube-p...size-overview/
Last edited by gerry72; May 12, 2017 at 09:13 AM.
Thread Starter
Le Mans Master
Joined: Jul 1999
Posts: 5,005
Likes: 38
From: jackson nj
Tube is always OD. Headers are made of tube.
Edit: Here's a link to clarify it beyond doubt: http://www.atc-mechanical.com/tube-p...size-overview/
Edit: Here's a link to clarify it beyond doubt: http://www.atc-mechanical.com/tube-p...size-overview/
gerry, according to your link, the O.D. is larger then the size advertised, as I copied and posted above. That would then mean the I.D. of a 1 3/4" header is in fact 1 3/4", not the O.D.
Last edited by Redvette_22; May 12, 2017 at 10:41 AM.
Thread Starter
Le Mans Master
Joined: Jul 1999
Posts: 5,005
Likes: 38
From: jackson nj
This is what I've always been under the impression of, however, I went to buy 1 7/8" headers for my car recently, and the vendor tried to say the O.D. was how they are sized.
Thread Starter
Le Mans Master
Joined: Jul 1999
Posts: 5,005
Likes: 38
From: jackson nj
That was always my understanding as well. So, if I want 1 7/8" headers for my 413, then the I.D. should be 1 7/8" and the O.D. somewhat larger...correct ?? That is what I expect anyway...am I right or wrong??
Le Mans Master
Joined: Jan 2006
Posts: 6,505
Likes: 139
From: Butler Pa
Wrong. Tubing, which is what headers are made from, is measured on the outside. The O.D. will be 1-7/8 and the I.D. will be smaller.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!
Joe Kucinski
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
The OD is the measured size for tubing. The ID will be determined by the gauge of the steel. Thicker steel smaller ID.
Le Mans Master
Joined: Apr 2007
Posts: 7,353
Likes: 72
From: Graceland in a Not Correctly Restored Stingray
Yep, tubing and pipe diameters are specified differently. My BB Hooker sidemount primaries are 2.125" OD, matching the sited dimension. FWIW, the engine sim software I use has entry fields for ODs, and a separate ones for gauges so it can most accurately perform exhaust flow calculations.