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Exhaust Manifold without AIR tubes

Discussion in 'Chevy Trucks' started by Nigel Tufnel, Apr 21, 2011.

  1. Nigel Tufnel

    Nigel Tufnel Junior Member
    Messages: 5

    I have an '86 K5 Blazer with a completely rebuilt 350 in it. When I did the rebuild, I couldn't't reuse the existing manifolds because they were heat warped so I put in a set of aftermarket headers. Well After two years of dealing with exhaust leaks, melting ignition wires, and baking plugs, I am going to bite the bullet and put in a set of stock exhaust manifolds. Dorman reproduces most of the years, but I need to get a set that does not have AIR and will also have dumps that clear the front axle. So with that said, the question I have is, what was the last year for Chevy to have trucks without the AIR tubes on the manifolds? I ripped all of the smog filters out of it when I did the rebuild and I don't want to have to deal with plugging up holes in a new manifold.

  2. B&B

    B&B PlowSite Fanatic
    Messages: 12,777

    All the Dorman replacement manifolds are drilled for AIR if it's for a vehicle application that could have included it (which covers about everything that would fit yours). They simply include plugs to plug the AIR ports on non equipped vehicles. Reduces p/n's that way.

    Running manifolds will be less expensive than the cash it requires to run headers without the problems commonly associated with them. Top quality headers that actually fit correctly, plug boots that won't burn and good gaskets to seal them reliably for the long haul requires a premium investment. Thus manifolds are less expensive even if you're including purchasing them new.
  3. Nigel Tufnel

    Nigel Tufnel Junior Member
    Messages: 5

    Thanks! At the time of the rebuild I didn't realize that dorman stocked the manifolds. I had a set of cheap-o heddman headers and two winters of slushy/salty water hitting the collectors, they are pretty much shot. Once a vehicle hits 25 years in NY, they are exempt from emission standards so all of the factory emission equipment is sitting in a milkcrate in the garage, so I won't have an issue getting it inspected. I didn't want to have to deal with making the stock airtubes "work" if they arn't getting used at all, so I figured I was going to have use a set from an earlier model. If Dorman has the plugs in the box, even better.

    Loosely related, but would you happen to know of anyone that still sells "test pipes?"
  4. TJS

    TJS PlowSite.com Addict
    Messages: 1,325

    This is what I did. I found factory manifolds and found some of the emission tube plugs and welded caps on them. It also has a complete exhaust build up on it. Truck is since gone.

  5. BlizzardBeater

    BlizzardBeater Senior Member
    from Maine
    Messages: 420

    Nice job TJS, TIG welders are amazing machines.