So last fall I decided to replace a rusted out exhaust system on my 90 Camaro. After removing everything, I came to the y-pipe and broke 2 of the studs. I proceeded to cut and drill them all out slightly larger to accept a simple nut and bolt only to find that I could not fit a bolt because of extra tight clearance. I will most likely just order a new set of replacements for it or find some used ones.


Another problem was the Mac y-pipe that was to my knowledge an stock upgrade that would work with stock manifolds. It did not, the passenger side was off by a number of inches. I will scrap that y-pipe since it also turned out to be somewhat poorly fitting in other areas as well.


I have on hand a 3" straight pipe to replace cat, a Dynomax intermediate to a Hooker Aerochamber with stock style tailpipes. My question that remains is the y-pipe and cat (or lack of if I end up utilizing the straight pipe). Since I will be using stock manifolds I am wondering if the Magnaflow 16450 y-pipe will bolt up to them? I noticed in a search that it only states fitment up to 89. Possibly the Hawks y-pipe but the price seems a bit steep.


This post by member eseibel67 pretty much sums up what I am looking into:
"For some, performance is the only consideration so headers are the only way to go. For the rest of us, there are more things to consider. Headers have a lot of negative drawbacks, so we use manifolds."

"By the way, I just did some exhaust work on an 88 LB9 5 speed. Used the Magnaflow 16450 Y pipe, a Walker 15622 Converter, and a DynoMax 3" catback. I highly endorse this setup if you want to keep stock manifolds. It fits great, sounds great, and I can feel a bump in performance at all RPM's."

 

There are at least two distinct V8 exhaust manifolds on 82-92 Camaros. Where people usually get into trouble with aftermarket Y-pipes, is they assume all TPI engines use the same manifolds, they don't. The passenger's manifolds have the outlets in different positions on the high output manifolds vs the LG4/L03 low output manifolds, in addition to having larger outlets. The other frequent hang-up is losing the cast iron spacer from the passenger's manifold outlet.

You'll need to match the manifolds to the y-pipe, or they won't fit.

 

Thanks for your input, I appreciate it! I happen to have a 1990 Iroc-Z with the LB9. That is the reason that I am now wondering what may work with the LB9 manifolds (other than stock) since I most definitely did exactly what you said most people do.


I'm thinking my only Y-pipe options are:
1. Stock
2. Magnaflow 16450 if it will work on a 90 LB9
3. Hawks Y-pipe

 

It's not quite that easy... LB9 could have either the HO or regular manifolds. Generally speaking, 90-up TPI cars without dual cats are going to have the regular manifolds. The Magnaflow is designed for HO manifolds. I'm not sure about the others, but the easy fix is to get a set of HO manifolds.

Any TPI car from 85-88 should have HO manifolds. Any dual cat car should have them. Once the manifolds are changed, the Y-pipe and everything else from typical TPI car will bolt up.

 

A search of Rock Auto as well as a quick EBAY search for HO manifolds both gave me a result of a Dorman part# 674-518 and 674-519 for the manifolds for both my 1990 and a 1987. Makes me wonder if one could really be sure based on the part numbers alone. They sure seem right but who knows.


I'm figuring that once I change them I can go ahead with the Magnaflow y-pipe and cat and the rest of my exhaust should finally bolt up.


All of this headache just to cruise like an old man when it's done.

 

If the photos are correct, 674518 and 674519 are the HO manifolds. Which really would make sense, they don't appear to offer the non-HO manifolds at all.

It's a bit of a wash, but a used pair could be found cheaper in the classifieds board here, but new aftermarket manifolds would prevent issues like stripped threads, cracks, etc. 6 of one, half dozen the other.

Don't forget the spacer for the passenger's side manifold.

 

 

Anyone? Am I correct in my thinking in my previous post or am I still off and missing something?


I want to button this thing up as soon as possible and get it on the road again.

 

What ever you do stay away from the flowtech y pipe (#11102yflt). I put one of these on my '87 and it was a huge pain in the butt. Total I had to cut 6" out of the system to get it to fit correctly. Here is a link to the pics of what I did. https://www.thirdgen.org/forums/memb...ml#post6024083

 

Story of my life, man. Story. Of. My. Life.