So, I'm trying to piece together a custom exhaust kit for my 1991 Z-28 with the L98. I've been reading the stickies on the exhaust page and just keep getting more and more confused, so I would greatly appreciate someone giving me some feedback one way or another on my planned set-up.

First off, I am going to have a local shop mandrel bend and fabricate the piping. I was told that 3" dual would be too big for an L98, so I was going to go with 2.5" Full Dual exhaust, would this be a good decision?


My next question is on Headers. I was considering Hookers, but wasn't sure which ones to pick. I was curious about the 2460's since they are decently priced, and my car is only a daily driver and the engine is mostly stock. However, I have been reading lots and lots of posts claiming these aren't good for performance and restrict exhaust gas flow. The others were the Hooker 2055, however these are much pricier, and I don't think I can buy them without the Y-Pipe, which I wouldn't use since I'm going to do a full dual system. Are the 2460's really bad as people say they are and should I just go with the 2055s? OR will the 2460's be sufficient for a street car? Regardless, I am going to get ceramic coated headers just so I can have the durability.

After the downpipes I was going to have electric cut-outs:
http://www.summitracing.com/parts/CMB-05-0021/

Behind the cut-outs, my next decision was for the catalytic converters (It is a daily driver street car, so it does need to stay emissions legal, and with good cut-outs, I'm not going to miss those 2 horsepower at the lights) The Cats I was considering were 2 of these magnaflow cats, without the AIR system, I was just curious if anyone else had used these and if they are high quality? http://www.summitracing.com/parts/MPE-49206/


The final part of my exhaust would be two Borla XR-1 Mufflers, I've heard some cars with these and like the sound. I was just curious as to any input on them good or bad http://www.summitracing.com/parts/BOR-40941/


Again, I am just looking for some feedback to whether or not this is a good set-up, and if not, what should I change.

Any help is gladly gladly appreciated, thank you so much in advance.

 

Also, if someone could tell me if 3" really is TOO much, or if 2.5" would be sufficient.

 

2.5" would suit a stock L98 better as the 3" would probably move your power and out of the usable range. I'd like to see how well all that fits under the car, especially with the 700r4.

 

Well, as for fitment, I'm fairly sure there won't be too many problems. The car already has dual-cats, and the aftermarket ones are pretty much the same size as the stock ones, give or take an inch. The cut-outs should fit easily side by side in the short section between the bottom of the downpipe and cats. The only real concern I have is the muffler placement will most likely have to be awkward. I was contemplating possibilities, and one that came to mind is having one muffler right after or right before the axle, and one where the stock muffler is. I haven't looked thoroughly at the underside in the car recently (My lift is occupied by a 72 Cheyenne) But with custom piping, I should be able to find somewhere for the mufflers to go.

 

2.5 will work just fine, but I would try and put the mufflers together, different spacing will likely cause different sounds and pressure will be different. I put mine in the driveshaft tunnel, but I used bullets.

 

I was originally going to use those, but I don't believe Borla makes the XR-1's in bullet form with 2.5" I could only find them in 3"

 

How about these from Dynomax?
http://www.summitracing.com/parts/WLK-24215/

I had them on my 67 Firebird, they're pretty loud though

 

Well, my main reason for choosing the XR1s is because I love the sound and the dynomax just don't do it for it, power isn't a big concern for me either since I'm going to have cutouts all the way at the top. Also even if they don't make them in 2.5 Diam. Round, if I'm getting custom piping, I'm sure they will fit somewhere.

A question of mine that no ones discussed is the Headers, which ones would be the best choice?

Edit: I checked Borlas website, the 5" round are not made in 2.5" diameter.

 

Save yourself some money and headaches, buy a set of dyno dons shorty headers and his 2.5 inch y pipe. Then put a cutout right after the y pipe, thats what I have and works great. Just sounds like your going to put a lot of labor into your exhaust setup, and may not see that great of results/