I am swapping my 3.4 L in my wife's 97' for a used 99' 3.4. The engine came with a different exhaust that I can't seem to identify. It looks like it is stainless instead of cast, and it has no heat shields. I would like to use it, but am not sure what to buy from the engine back because I don't know what brand it is. It doesn't seem that it is a factory setup. The parts guy at the local dealer told me all of the 3.4's had cast headers with heat shields. Any help would be much appreciated. BTW this forum is awesome! I've learned so much on here.
Anyone recognize this exhaust?
- Thread starter Powturn
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I am swapping my 3.4 L in my wife's 97' for a used 99' 3.4. The engine came with a different exhaust that I can't seem to identify. It looks like it is stainless instead of cast, and it has no heat shields. I would like to use it, but am not sure what to buy from the engine back because I don't know what brand it is. It doesn't seem that it is a factory setup. The parts guy at the local dealer told me all of the 3.4's had cast headers with heat shields. Any help would be much appreciated. BTW this forum is awesome! I've learned so much on here.
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Hmm, that's what I thought too. It made me second guess that when the dealer parts guy told me that all 3.4's had cast manifolds. Also the parts fiche shows heat shields on everything. This one has no heat shields & no where to mount any. The triangular outlet definitely looks like the later model dual cat exhausts though. Anyone know which is better? Original cast manifolds with single cat or later model stainless with two cats?
TheDurk
Elite Member
Well, you don't have a lot of choice. You can't bolt a two-cat crossover to a one-cat pipe or a one-cat crossover to a two-cat front cat. (See how the one-cat crossover ends in two pipes, but the two-cat ends in one pipe?) If you put a one-cat exhaust/crossover system on a two-cat ECU you will get a permanent CEL (P0420). So I'd worry more about matching sensors/ECU/cats/manifold/crossovers so that they bolt-up and work, rather than speculating about which is 'better'. What I don't know is whether you can bolt a one-cat crossover to a two cat manifold and vice versa. They use the same gasket at that point.
Also, the two-cat Cali manifolds use the same heat shields as a one-cat Federal, at least on a '99 3.4 (17168-62051 on both sides)
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Thanks for the replies. I get what your saying. I am definitely more interested in everything working right and not causing myself more problems. It's just so tempting to use this newer exhaust instead of my rusty old one off my original engine. I was considering changing everything out beyond the engine to bolt up to this one, but not worth it if it's going to cause a CEL. Also here is a side shot. See how there are no studs for mounting heat shields. Weird huh?
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