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Discussion Starter · #1 ·

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01 Astro RWD Cargo, 97 AWD Mark III
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Why so small on the pipes?
I would think 2.5" minimum with that V8.
 

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I figured 2- 2" pipes is as good as 1- 3" pipe and the manifold to pipe hole is 2" on both
 

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Common Sense + Critical Thinking
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Engine Masters did an episode on that, on a 350hp SBC true dual exhaust there was absolutely zero performance difference between the 2.5" and 3.0" exhaust pipes. So other than costing more, being heavier and having a different sound there was no benefit to the 3.0" dual exhaust. That tells me that the max I would bother with is 2.5" for that setup. Would have been cool to see the difference between a 2.0" and a 2.5" exhaust, the calculator says it should be fine with 2" for dual, and 3" if you were running a single. Here is an online calculator you can use: Exhaust Size Calculator

Only if you are going to throw an engine in there that requires more airflow would it make sense IMO. Stroked/bored/boosted, then it probably makes sense to go beyond a 2.5" dual.
 

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01 Astro RWD Cargo, 97 AWD Mark III
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I didn't catch the duals part. Makes sense that way.
 

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Discussion Starter · #6 ·
Someday I hope to drop a reman 350 in it but that's about it. Because it is AWD and will be 4x4 eventually I need torque more then horse power so no need for bigger exhaust. besides bigger stuff under a vehicle used for trails and such is more to get hung up on stuff. Years ago I built K5 blazers for serious off road and I smashed mufflers and pipes up often lol. Even destroyed a set of hooker headers once jumping a pile of dirt. Of course I will not do that kind of stuff with my van but I learned from it lol.
 

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2000 Lifted 4x4 Astro 92 V8-350 Shorty
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..the calculator says it should be fine with 2" for dual, and 3" if you were running a single.
Here is an online calculator you can use: Exhaust Size Calculator
Completely AGREE. Especially considering it's dual.
In fact, the 2" may actually be more beneficial for midrange torque and fuel economy.
Good job!

The "HP Calculator" mentions HP.. but left out RPM's.
Good for generalizations... but even then there are still multiple other factors as well.
 
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