I did a search found a few questions but no answers.

Is there a difference between the intermediate pipe as the years change or is it from the cat up thats different?

Also if anyone knows what the largest I pipe is from the factory it would help alot! Or can say "My Iroc had XX size pipe from the factory"

I found a source that sells pre-bent OEM replacment peices nearly all of intermediate pipes have different part numbers yet they do not list diameter . I'd like to stay with a minimum of 2 1/2 pipe if possible since that would be fine for this setup of course larger would be better. Of yea and the pipes are very inexpensive, the stock I pipe over the axle is only $24 for the bird but again has to be ordered and no size listed.

Well according to the tech data page the mid year 83 L69 had 2.75in pipe. Does that continue as the years go on? The 2 Z28's (85, 86) Ive owned had the exh replaced with cheezy 2 1/4 pipe back when I got them so I cant verify it. 2.75in pipe would do just fine if someone can verify a year and a vin engine digit for me.

I'm pretty sure there were no 3" I-pipes from the factory...

The tech data page said it was close in the 83 L69. Bad news though. I found a site with the same part numbers as the catalog I have. Apperently the L69 HO I pipe isnt avalible. Funny because the Y pipe still is.

2.75" is the largest factory pipe I've heard about.

The differences had to do with the flange to the cat. Some 2 bolt, some 4 (I believe that's what they were, anyway).

You could just get one from headman or another company. They have a 3" I pipe.

Yea but a $30 2.75 pipe would have been killer. I guess $30 for a stock pipe isnt too bad if you have a 2.8

How about the '86-'90 TPI single cat pipe? Maremont 369733, $33 from Checker. VIN F or 8.

57 do you have any measurments on that pipe?

Found it!! 2.5in Perfect for a smooth sounding street machine!...with a cut out

At least I'll be getting somthing done soon now.


Thanks 57!

Called Checker and got it ordered. Had a talk with the CSR guy about me not knowing I could order this stuff from them too. It will be in friday $23.

Here I thought it would be 2.75".

Let us know when you get it.

Well got in in friday, in just not done. The pipe was well worth the money but tail pipes that were on the old muffler needed to be hacked off and re-angled besides I paid $40 a pop for the tips on my original setup 4 years ago that need a good home. Also did some searching on the cutout I got from Summit. I'm not going to use it, the pics of it installed on thirdgens show it's way to low to the ground.

I'm going to run over to the shop and snap a few pics as soon as my $5 camera charges.

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So, was it 2.5" or 2.75"?

I especially like that one...

I figured you would like that one Thats the sticker that came in the info packet you sent my way a few years back.

It's 2.5 OD pipe which is smaller then my Y pipe which is 2.5ID but I'm not worried about it.

I did get it done'ish sunday night but ran out of shielding gas so I had to switch to flux core half way. Flux core just donsent weld verticaly for me, so theres a couple touch up spot to be done.

It sounds real nice. I had this muffler on the old engine a few months before it got pulled, it sounds a whole lot better now. I just cant say the same for the engine noise. I did take it around the block reguardless. I sure do love how smooth 327's are in the upper RPM range

I'm still disappointed that it's a 2.5" pipe, when it's supposed to be for the applications that originally came with 2.75" pipe.