Headers or iron manifolds?

[Supercharged111]

I'll have to get under Rawhide and see what the exhaust manifold outlets and downpipes measure out. I have heard that the one tons got bigger exhaust, and maybe the 8 lug 2500s did too. I think everything forward of the mufflers is stock and original. It looks bigger than what's on the Burb, anyway....

8 lug pipes are bigger than 5 lug pipes from the General.

 

[HotWheelsBurban]

Big truck, big pipes, big rumble especially when leaning on the throttle....

 

[L31MaxExpress]

8 lug pipes are bigger than 5 lug pipes from the General.

Going off memory, the L31s in lighter GVWs have 2" OD pipes (my 99 Tahoe was born with that garbage) and the 8600+ are 2.75" OD. The vans have dual 3" OD, atleast my 97 did and still does. Why GM used the odd 2.75" on the trucks has always been mystery to me considering the vans are 3" OD.

 

[L31MaxExpress]

Big truck, big pipes, big rumble especially when leaning on the throttle....

I think it had more to do with keeping the exhaust system and cats cooler when you have the go pedal hammered to the floor in the heavier trucks while towing. The trucks with larger pipes had catalytic converters that were massive compared to the smaller piped trucks.

 

[SUBURBAN5]

I'll have to get under Rawhide and see what the exhaust manifold outlets and downpipes measure out. I have heard that the one tons got bigger exhaust, and maybe the 8 lug 2500s did too. I think everything forward of the mufflers is stock and original. It looks bigger than what's on the Burb, anyway....

You know don't be surprised if it's the same. Btw the manifolds from stock were made for diesels but gm used it on all engine applications. Which is why there lasted so long.

 

[Erik the Awful]

Going off memory, the L31s in lighter GVWs have 2" OD pipes

1 7/8", and crush-bent.

 

[SUBURBAN5]

1 7/8", and crush-bent.

Wasn't crush bent on earlier 400s not later? My original exhaust on the burb was smooth bends from front to back.

 

[L31MaxExpress]

You know don't be surprised if it's the same. Btw the manifolds from stock were made for diesels but gm used it on all engine applications. Which is why there lasted so long.

My OE manifolds did not last 65K miles. Both banks cracked nearly in half. Very common place for them to crack where mine cracked as well.

 

[SUBURBAN5]

My OE manifolds did not last 65K miles. Both banks cracked nearly in half. Very common place for them to crack where mine cracked as well.

I'm sure not all of them did. Mine lasted 425k miles. I'm sure there hit and miss but still better then today's options. I just bought a dorman 3 months ago and discovered a hair line crack on the left side...

 

[L31MaxExpress]

GM went to manifolds built like this on trucks, vans, RVs and Corvettes to eliminate cracking. My 83 van had these on it from GM.

You must be registered for see images attach