What "size" are These B&B Headers
 

Folks,

Looking for some clarification on B&B header sizes.

Understand B&B made 1 5/8" and 1 3/4" headers, with the 1 5/8" header preferred for a 3.2L engine.

Are B&B header sizes based upon the outside diameter (O.D) of the primary tubes, or inside diameter (I.D)?

What size are the headers in the following pictures (same header measured from OD and ID points):

OD measurement of primary shows 1 3/4"
http://forums.pelicanparts.com/uploa...1414638370.jpg


ID measurement shows 1.610" (1.625" = 1 5/8")
http://forums.pelicanparts.com/uploa...1414638459.jpg


Thanks,
Gordo

For B&B 1 3/4" OD is 1 5/8" ID

the above are 1 5/8" and probably have the correct for a 3.2 round heat inlets

B&B 1 3/4 Header O.D.
 

Thanks Bill,

Not sure I'm following though - I thought B&B specified header sizes based on OD of the primaries. If that's the case, wouldn't the above headers be specified as the B&B 1 3/4" version?

Also, in this thread http://forums.pelicanparts.com/porsche-911-technical-forum/64543-header-pipe-thicknesses-what-you-running.html you said that B&B headers come in 2 sizes: 1 5/8" OD and 1 3/4 OD.

Lastly, if these aren't B&B's 1 3/4" headers - then what is the primary OD on the 1 3/4" versions?

Thanks again,

Gordo

You're right, I answered too early in the AM. I just checked the measurements on mine which are 1.75" OD and 1 5/8" ID, the same as those.