Stock exhaust configuration

[Layne02]

Hi everyone, Im trying to figure out the original exhaust on an 87 GMC Sierra Classic. Ok , part of it is completely missing so I am trying to search and piece together what the thing looks like and what parts were originally there, I am buying all new cause the old one was totally shot. So far I have the y pipe that goes to what is either the muffler or a converter, its wide and flat and kinda oval shaped, then a single pipe that goes into something,( this is part that is gone) , then theres two smaller tailpipes that both exit rear driver side. So what I am trying to figure out is, is the part I am missing the muffler and is the part I still have that is off the y pipe the converter? I looked it up on Walker Exhaust and thats how they have it. Anybody still have an original exhaust system that can help?

 

[RangRayy]

More than likely you're missing a muffler. Manifolds to Y pipe into catalytic converter then into a muffler to an exit at the rear of the truck. That's how mine is on my '87, until I replace with headers and dual exhaust in a week or so.

But sounds like your setup was a single in dual out muffler of some kind.

 

[Georgeb]

You are missing the muffler. Mine was 3" single in and single out then a Y that split it into the two tail pipes that exit on the drivers side.

 

[Layne02]

Thanks for replies, yea I looked and looked last nite and finally figured out this is what was a pellet style converter, doesn't really look like the newer ones. We dont have to deal with any emissions testing here at all, could I just leave it off and run a straight pipe or would that give me a problem with how it runs? Thanks

 

[RangRayy]

It's a pancake style converter. The exact same as I have. Worth a little bit of money if i remember correct at certain scrap yards, just depends on your area. Also if someone hasn't popped open the hole and pulled all the platinum crystals out. Shouldn't have any issues. If you don't have emissions testing why not put a set of headers on as well and delete the AIR pump?

Headers, dual 2 1/4 pipes with an H pipe to either dual mufflers or a dual in dual out muffler then exit wherever you want... Get a better flowing exhaust allowing your engine to breathe better. This setup is what I am doing to my '87 but along with a carb conversion.

 

[Layne02]

I'm fine with keeping exhaust manifolds and even a single pipe, if taking converter off wouldnt cause it to run bad I am fine with that too. Its just for around town driving , no extra horsepower needed really, but what do you mean about the AIR pump? I am trying to learn all this stuff, thanks again everyone.

 

[RangRayy]

The air pump is the smog pump. Should be under your alternator. Helps with emissions by pumping air into the exhaust to help with cleaner air going out the tail pipe.

Read through this....
http://m.smogtips.com/air.cfm

 

[Layne02]

Theres not anything like that on mine, may have been removed before I got it