Hello,
I ordered some headers for my Iroc-z. I got the 68478 Hedman shorties with the thermal coating. Originally I was planning on having a local exhaust shop fab up the Y-pipe, but now I am considering ordering one instead. Only problem is that the y-pipe that Hedman offers for the socket flange (part#17478) Y's into 2.5". I have a 3" high-flow catalytic converter on the car now, with 3" after that cat into a single-inlet (3"), dual (2.5") outlet muffler (unknown brand). My question is. Would I be able to use (part#17470, this part number Y's into 3") cut off the flanges and simply have those welded to the collector reducers that come with the headers? The reason I don't want to go with the exhaust shop is that he only has the crush-type pipe bender and I don't want any restriction before the cat.

The engine specs to the best of my knowledge are:
-350 bored .030
-Brodix Aluminum heads (Not sure the runner size) they were on the car when I bought it.
-TPIS bigmouth base.
-52mm throttle body.
-Stock appearing intake runners.
-Comp 260H cam, (.440 in, .440 ex)

New to the forum and to third-gen's. Thanks in advance for any advice/help!

 

The Y pipe comes with a 2.5 to 3.0 adapter... I had a friend that works at a wholesale exhaust warehouse mandrel bend me a 3.0inch pipe where the 2.5 was on my Hedman 17470 Y pipe and it worked out great... Oh and welcome to the forum!!

Mark.

 

Thanks!
So lets say I go that route, but can't get that 3" section mandrel bent. Would that even be worth it?

 

If you cant get it mandrel bent don't go with the 3 inch pipe, just stick with what it has which is a 2.5 inch mandrel bend. To be totally honest I couldn't feel any difference in the seat of the pants anyway.


Mark.