C3 AIR/Exhaust Manifold/Extension Tubes

[Paul L.]

Re: C3 AIR/Exhaust Manifold/Extension Tubes

Joe,
You are a jewel! I will order those #12338013 tubes tomorrow. They were the last pieces needed for my C3 1979 AIR exhaust manifold rebuild and I am very relieved. Thank you.

[Paul L.]

Re: C3 AIR/Exhaust Manifold/Extension Tubes

It seems that that was a GMC truck application after 1978. Bizarre how GM changes parts usage!

[Paul L.]

Re: C3 AIR/Exhaust Manifold/Extension Tubes

For anyone who wondered what I was speaking of and what they look like, here is a pic. They arrived today. Thanks to All for the advice!

[Clem Z.]

design change

the design change is that the orignal ones were just straight tubes,open at both ends. these has a crimp at the one end and slots in the sides to change the direction of the air entering the exhaust port.

[John H.]

Re: design change

Here's what the original A.I.R. tubes look like - click on the link below (replaced mine with #10 x 1/2" flat head machine screws to plug the holes, then re-installed the A.I.R. manifolds, and gutted the pump).




Original Design A.I.R. Tubes

[Paul L.]

Re: design change

This may be trivia but should the open slots be positioned east-west or north-south in the manifold?

[John H.]

Re: design change

With no indexing provisions, I'm sure nobody paid any attention - just dropped 'em in and installed the manifold tube nuts.