SLC exhaust options

How are people running their exhausts in the SLC? I've seen pics with turn downs in front of the rear wheels, and some exiting the diffuser. Can anyone post up pics of exhaust routing options?

Are people running crossovers (h-pipe), x-pipe, or straight duals? I haven't heard a true dual exhaust in a SBC motor that sounded "right" to me. The crossovers sound better.


Active Member
I'll just be running straight pipes out the back - I'd question if there's enough room to effectively do an X/H in the back?

I won't be running side exhaust due to the fact it'd bring the exhaust pipes really close to both my battery and fuel stuff.


Active Member
Hello again RM
It is my goal to X pipe mine although I do not know just yet which way I am going to accomplish this, it is currently on my activities list. I would like to have a centered above the transaxle setup like the GT40s, but this would cause the rear body to be modded to accommodate and I'm not sure I'm into doing that much added work to get it done. (I have not worked out a number to our other discussion)

Crash, I have considered the muffler you show but with stock body there is no place to put a single muffler. The rear body is too low to install it in a centered location. The new 'street' tail may offer enough room above the rear subframe but I doubt it.


New Member
Seeing the SLC that was at TH with the street car tail, I bet it WOULD fit, but I'm sure Fran would know for sure. Appears to be plenty of room for this in a GTM.

Race tracks are requiring lower and lower noise levels each year, so even if you are going to just track the car, you may want to consider adding mufflers.
I will definitely be running mufflers. I'm leaning towards the Borla Multi-Core XR-1 options right now. I'm won't know which version until until I see what fits though. I'm also thinking of adding empty cans as resonators (non-filled/baffled) to help mitigate the db level after the collectors and before the cats. I'm looking to design the quietest yet least restrictive exhaust I can. Those goals tend to work against each other though. :(

Mesa: I ordered my SLC with the Street Tail option, but I'm not exactly sure what that will buy in terms of space above the Ricardo. We'll see in a couple of weeks when it's here, but I wanted to get the ideas flowing before it gets here.

Alex: The nice thing about Crossovers is that it doesn't effect power much whether the crossover is 7" or 30", nor if it's a slightly smaller diameter than the main pipes. It helps equalize the exhaust waves, and sometimes offers slightly better performance, but definitely helps with the exhaust note. An X seems like it would be trickier in the SLC without seeing detailed exhaust routing options from pictures.


Active Member
You'll have to visualize here

but your'e definitely not getting your crossover underneath the transaxle cage. So it seems to me you're stuck on top. But as Rob pointed out the clip slopes downwards at a steep angle.

It may very well be possible, but I'm just not seeing it (without a lot of modification)

edit: I may be way off base here, but I see you want to run mufflers, resonators, a h/x .... I think it would be quite the chore to fit all that plumbing there and have equal length headers (I'd think the equal length part is more important than the other stuff?)


Bronze Supporter
The rear clip is only about 1-3/4" above the chassis brace tubing at the back.
Exhaust could be either out the back or side exhaust choices right now. A crossover
may (smaller diameter) just fit underneath the front of the gearbox, but I doubt it.

If you're into doing some fiberglass modifications, you can make anything fit!
What about running the secondaries under the half shaft, up next to the trans, through crossover muffler like the one I referrenced, and then out the back? You could place the muffler behind the frame and still above the trans.

The SLC at TH had, IIRC, three mufflers on each side secondary tube, and they went back and forth in this area. I think you could possibly build a better sounding, less complicated setup using the Magnaflow 12599 or something like it.
Would it be possible to modify the rear chassis brace so that it ties into the gearbox instead of going straight across the suspension pickups? If the engine is solid mounted, dropping the brace would likely buy a couple inches of clearance in the center.

Of course, if the engine is poly mounted, tying the brace into the gearbox would be a no-go.
Not recommended as the transaxle case is not designed to carry that kind of load... The Xtrac in the #18 race car is designed to carry load ..hence the integrated mounting system we designed for it...potentially compromising the chassis structure for an exhaust may not be the best casue of action...but stranger things have been known to happen
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Bronze Supporter
There is barely enough room to do a crossover underneath the rear of the LS engine in the SL-C, using a "flattened" or oval section tube of about 2.5" (long) diameter. May decrease ground clearance just a bit. Long road to travel for a crossover.
I also looked into this and decided it was not worth the effort required. Ditto on modifying the bodywork. I did like the "snorkles" on the race car, may fuss around a little with something like them to feed the air intake, undecided right now.

Input Fran?? wink!


Active Member
Well, since we're talking about exhaust-wants, I want 180* headers!

My friend wants to fab them too, but we have no clue where to crossthem over, lol lol lol!

Fran, we want 180*s! We wants 180s! :D


Active Member
Buy an RCR40 THEN....nuff said.

962's dont have 180's..neither does an Audi R8/10/15....or any Ferrari race car....:tongue3:
Oh sure, rain on the exhaust parade :p

Although I wonder if one could cross-over above the rear clip and then head back down ..... hmmmmm, can a race scoop cover the whole rear clip? :stunned:

It's probably a good thing I lack Rob's fabrication skills, otherwise some very unusual things could be happen to the car :stunned::stunned::stunned:
I am moving forward with a crossover tube on my LS SLC with new tail: I have used a 5" CLR 3" SS J-Bend from flange up and back to muffler. As the radius straightens out I will connect a 3" or 2.5" straight tube back under axle, turning under Ricardo just in front of rear cross member. Converting to a short piece of oval NASCAR tubing for area under Ricardo (a 3" oval tube is only 2 1/4" tall and will not be lowest point on drive train). After the "bell housing" the bottom of the Ricardo is raised which clears the rear cross member. With a bit of heat shielding it should have no impact on Ricardo. My goal for next couple of weeks is to complete wiring to DigiDash and sending units and hopefully have a successful first start up. Then I will fab crossover. I will post pic's when I start but can post pic's of what I have so far if helpful.

Hello gents!

I must in all honesty say that I find it really strange that a well built car like the SL-C does not have a good solution for a muffled exhaust system. I meen, look at the #18 car ! Looks like Fran & Gang pulled it off really nice. Yes I can see the difficulty making a functional x-over, but why all the fuss? No I don`t have an SL-C in my garage yet, but how hard can it be?

How about a Porsche 911 Fabspeed muffler like this? 2 in and 2 out, and pretty slim (one way at least)

It could have been put upside down in reg. to the pictures, that way the pipe from the cats could go underneath the half shafts and straight into the muffler. Maybe ??......... Any one?