1980 C30 SBC (M code) factory exhaust configuration?

[fordguy40]

I apologize if this has been answered, but the search function seems to be broken on my end

Truck currently has a dumped true dual setup with no cats. Our truck appears to have had dual exhaust from the factory because of the riveted-on remnants of the factory tailpipe hangers on both sides of the frame, ahead of the shackles. The truck was first sold in CA to my wife's grandfather, so I'm guessing that means it's not "federal". Checked Walker's site for the factory exhaust layout, but they only list the non-catalytic converter, single exhaust setup.

Could someone please confirm that this truck would have had dual exhaust and a y-pipe going into a single converter? Also, can anyone who's gone true dual/dual cats tell me what kind of grief I'm potentially looking at when I go to smog it?

[Palf70Step]

I have never heard of a factory dual exhaust on trucks that came with a cat, especially if it was first sold in CA.

[Keith Seymore]

Your truck did not come with a convertor (for California emissions or Federal emissions).

K

https://www.gmheritagecenter.com/doc...olet-Truck.pdf

[fordguy40]

Thanks for the replies, guys. I'm hoping that you're right and it didn't have a converter, but this being California, you never know. I've also found info that supports the one-ton trucks not having cats in '80, but only thing is there's a sticker on the driver's side sun visor that refers to the converter, and I'd need to double-check, but possibly the word "catalyst" on the air cleaner sticker. Grandpa supposedly wasn't the type to modify his vehicles and this thing's supposed to have never been wrecked, so I'm fairly confident it's original for the most part.

[Keith Seymore]

Originally Posted by fordguy40

... but this being California, you never know.

Actually...you do know.

That's official GM documentation from the era in which your truck was built.

If some local guy at the emissions shed wants to argue with that then he is bumping heads with the people that designed and built your truck.

We use those charts during the design process, to make sure we have all of the permutations covered and communicate with the rest of the organization, and then they are distributed for Marketing use and stored for posterity.

We've used them in the past to help in importing to foreign countries, to show what options were available, or applicable GVW ratings, or that the vehicle has the proper content, so their use for a similar activity in California is not much of a stretch.

K

[fordguy40]

I'll be sure to take this information with me when the time comes to smog it....thanks, Keith. Having never owned a truck this old, it's just odd to me that even up to 1980 you could still get one in California without a converter.

And looking under the truck last night, I might've mistaken a couple of bushing'd, L-shaped brackets bolted to a hole on each side of the frame for exhaust hanger mounts that I've seen on other squares on the internet, which could mean this thing had aftermarket tailpipes at one time? What's left of the riveted factory hanger is only on the driver's side, which coincides with the info from the gm heritage center (1980 LT9 trucks had single exhaust).