2nd Gen Non-Engine/Transmission Stock exhaust?

[jwebster]

I'm looking to replace the tailpipe section of my exhaust system. The truck is a 1997 with a manual transmission. I measured the outlet at the muffler, and it measures 4" OD. I was under the impression that the system was 3" all the way, besides the section between the muffler and resonator. I want to make sure I'm getting the right part. I'm an electrician and am familiar with nominal sizes for electrical related conduit, but how is exhaust pipe measured?

This is what I found listed to fit, its listed as 3" pipe:
Walker 55070 Exhaust Tail Pipe https://www.amazon.com/dp/B000C94FBY/ref=cm_sw_r_cp_api_WeGkyb5KVMTFX

Something seems off. Is my exhaust not stock? Down pipe to the resonator sure looks smaller, like 3". Thanks for any help!
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[GAmes]

It is 3" to the front of the cat, then 4". I'm reading your link that the pipe is 4".

 

[jwebster]

Strange, I was referencing the same part number on O'reillys website where the specs showed 3" as the diameter, but I see now under product dimensions on amazon it does say 4". Thanks for clarification on the fact that from muffler back is 4" stock. I suppose I should assume the O'reilly website is incorrect?

http://m.oreillyauto.com/h5/r/oap/s..._55070_1095904_4774&search=true&keyword=55070

 

[GAmes]

Who knows? What I can tell you is my stock cat and muffler are stored in my shop in case they ever start smog checks here. They are identical to the ones you have pictured.

 

[Bob4x4]

It is also easy to use a full4" down pipe and modify the cat inlet to 4"