Just an FYI, this combo worked great on my LS swap with LSX Innovations engine mounts and Hawks T56 crossmember. I had to fab up a custom hanger under the passenger side frame rail, but other than that the exhaust bolted right in. Really economical way to do it, I was prepared to have to cut the exhaust up to get it to work, glad I didn't have to. Will post pics, it's nice and tight to the underside of the car. Hope this helps someone! Sounds awesome too.

 

thanks for the heads up, planning out my swap this year - I may just copy you

 

Any chance of a sound clip or pics?

 

 

awesome thanks!

 

Embarrassed of those photos - still cleaning up after the 6 month swap. Should give you a good look at that exhaust though - hangs just below the subframe connectors - no further down than the Speed Engineering passenger header. I do have a founders panhard relocation kit but it doesn't look like the Blackhearts need it.

 

Nice and no cutting huh. I may look at that.

 

thinking about going this direction as well with my upcoming LS3 swap. Seems like a great solution to not have to have a custom exhaust made. My thoughts are to use the holley engine mounts and t56 crossmember, with their true dual exhaust and speed engineering 1 7/8 headers. Be great to save a few bucks over the holley headers if the Speed engineering are fitting up nicely and be great to not have to cut and weld a brand new exhaust.

Has anyone else had success with this combo?

 

Do you have a part number to the setup you used
thank you

 

For which part?

Speed Engineering 1 7/8 Headers can be found here:
https://www.speed-engineering.com/ls...2-ls3-ls6.html


Holley has a full line of Thirdgen LS Swap Parts:
https://ls1tech.com/forums/conversio...preview-4.html
Post #71 listed all the part numbers.
70101316-RHKR- 1-3/4” x 3” long-tube headers, 82-92 F-body LS swap, stainless steel
70101315-RHKR- 1-7/8” x 3” long-tube headers, 82-92 F-body LS swap, stainless steel
71221003HKR- 82-92 F-body LS swap engine mounting bracket kit
71222005HKR- 84-92 F-body LS swap transmission crossmember
71223003HKR- LS swap 4L80/4L85 transmission crossmember adapter bracket
71223004HKR- LS swap 4L60-4L70 transmission crossmember adapter bracket
70501326-RHKR- 82-92 F-body header-back exhaust system, 2.5" - 304SS - Auto Trans
70501426-RHKR- 82-92 F-body header-back exhaust system, 2.5" - 409SS - Auto Trans
70501339-RHKR- 82-92 F-body header-back exhaust system, 2.5" - 304SS - T56 Trans
70501439-RHKR- 82-92 F-body header-back exhaust system, 2.5" - 409SS - T56 Trans
71223006HKR- 82-92 F-body fuel/brake line heat shield
71223007HKR- LS engine starter heat shield

Holley also now offers headers in mild steel for about $700. Still a lot more than the Speed Engineering ones at $300. I am deciding if I should go with the speed engineering ones, or spend the extra on the Holley Headers for peace of mind. Big benefit of Holley is that I know for (almost) certain that everything should bolt right up if I use the Holley mounts and trans crossmember as well.

 

Thanks for reply. I was looking for the part number for the exhaust system from headers back. Which you provided
I might have to try this setup
Thank You

 

I know this is one of those ideas that takes money to make money, but.....

..... Stainless Works will make whatever you want if you drop the car off at their facility. They will mock it up, take measurements, and then put the numbers in there mandrel bender and pop out a beautiful mandrel bent system. This will cost between $5k - $7k. But once the measurements are the system they can pop out more kits for you at a regular price. Sell some kits and it's all paid off.

 

I've been considering dual 3 in exhaust for myself. Buying and modifying a 4th gen kit definitely seems appealing. But they're all super freaking loud.

The most difficult piece to make is the over the axle tube. One of the ideas running through my head is to buy 2 of those pieces from a high quality single 3 in system that is known to fit real well. That way I have two pipes that are identical and can be tucked together really tight. Situate them anyway it can fit, and then build out the rest custom.

 

My plan is to run kooks cats and replace the mufflers that come with it with something else. Hopefully that dampens it down enough. I have a feeling this will still be too loud. My neighbor has a whipple'd GT mustang with headers, no cats, and exhaust and it shakes my house when he fires it up. I don't want that.

 

Cars sound bad when they're loud for the sake of being loud. The newer Mustangs fall in that category. They make the list of the top 4 things I hate to listen to while I'm driving.

I hate loud Harley bikes
I hate loud 4 cylinders
I hate loud Dodge Cummins diesels
I now I hate loud Coyote Mustangs

 

I have this setup, too and it sounds good but not too loud. Really fits nice and tight under the car.

 

Ok So I went ahead and ordered this kit
my first review after taking it out of the box so far is 50/50.
What I liked about it.
And this is just a quick check to see if it would fit. Is that the pipes to fit right onto the speed engineering headers and also makes it past the hawks t56 crossmemeber Then the x-pipe right onto that. And seems to tuck under the car nice

The things I didnt like.
Not all the joints are slip joints. Some just butt together with a clamp.( guaranteed to leak)
after spending that kind of coin. I would expect slip joints at least Not some **** butt joints.
So I'm gonna either send it back. Or was looking to make my own slip joint by buying a section of pipe and welding one side and clamping the other

My setup is speed engineering headers..hawks motor mounts and hawks t56 crossmemeber
and so far just a simple.check the pipes do slip on the headers and past the crossmemeber. Which from what I understand if it gets that far your good togo.
If I decide to keep it. I will be installing over the holidays. As then I will.have time. So I will.update this thread with pics and anything i.will be doing.
just wanted to give a quick review after taking it out of the box

 

I actually liked the butt joints. It made assembly much easier by pushing in place and slipping the clamp over the joint. Yes, they will leak. After installation, each joint leaked drops of water. I packed each joint with muffler sealer which took care of the leaks.

 

Use Permatex Ultra Copper on the joints for a good seal.

 

EDIT: (I found what I was looking for in the links you posted, thanks for all the info!) Any chance you have some better pictures of the exhaust? Looking for how it fits under the car. As of right now this seems to be the best way to go that doesn’t require a custom y-pipe to be made. Not a fan of true duals but if it's a bolt on and go, I’m down.

 

Just test fit before going under car.

From under the car. Roughly in place

Just another pic

I decided to go ahead and install the exhaust So far it's going pretty good. Trying to take my time adjust and measure things as I go As u can see in the pics I already need to turn my clamps around.
the two pipes slid right onto my headers ( speed engineering) and the x-pipe cleared the trans and crossmember( hawks) I will have to add one hanger so far on the passenger side. The hooker crossmemeber has it built in. Hawks does not.
so one minor thing.
Will update as I move forward.

 

Got alittle more done today.
as earlier in this thread I was really not happy about the but joints. So I went ahead and made my own slip joints.
so far I'm really happy with the way this is going in. I still have to hang the mufflers and then really fit it all. And adjust. Over the axel looks alittle tight but nothing a little tap here and there on the heat shield wont take care of

An over all pic of the x-pipe and over the axle pipes with the slip joints.

A close up of the slip joints i made. I marked the pipe so i can cut the notches for a band clamp. Gonna put it all together then mark again to see if there is any difference.
then measure for the the notches so I know how deep to cut them.

 

Thanks for the pictures. I'm curious how the rest of it will turn out.

 

You got me looking around again. It seems that the Flowmaster merge into 4" exhaust works really well. I even see some people scrapping their 3-inch duals in favor of the flowmaster Y, and picking up power if they dump the single before the axle.

 

Update:
The exhaust is in. And I must say I'm pretty pleased.with the way it all came together. Fits nice a tight under the car.
Not really that loud either. I was expecting much louder, but I'm happy it's not. Perfect for me and wife to cruise around in and still carry a conversation.
ok..wont make you wait any longer Here are some more pics.

Looking back from the passenger side. U can see it doesnt even hang down lower than my sub-frame connectors.

This is of the passenger side header The header itself is probibly the lowest part of the entire exhaust.

 

I have this setup with speed engineering headers as well. Sorry I only have a couple of photos that aren't great but hoping this will help show just how much clearance you get with them. I did have to add a 2-3 inch extension on the drivers side header to get everything lined up properly but super happy with how everything turned out. Combine it with the hooker blackheart crossmember and I could take this thing off road

​​​​​​​

 

I just bought the Blackheart true duals kit based on this thread

 

You will be happy.
When the weather gets better here in chicago I would like to get a video up and more pics.
I know my reviews are alittle mixed. But in the end I'm pretty happy with the exhaust.
Install is pretty straight forward Just take your time get everything in and start adjusting before u tighten it all down.
oh. And it sounds good without major drone.

 

Does anyone have this setup with a 4l60e? If so, how does it fit?

 

If I’m not mistaken, the crossmember fits exactly the same. I think their crossmember is made to fit a t56 by itself and then they make a bracket that allows you to mount a 4l60 to it. Could be wrong though.

it’s by far the best crossmember for ground and exhaust clearance.

 

I meant the speed engineering headers compatibility with the 4l60e automatic transmission set of true dual 2.5" holley blackheart system

 

I'm running the Speed Engineering headers with this exhaust and a 4l60e. If you don't run the Holley crossmember, you'll have to fab up a little bracket to hold the passenger side exhaust hanger in that area, but that's rather minor.

And to echo what everyone else has said, I also really like the sound. I thought those small mufflers wouldn't do much and the car would be obnoxiously loud, but it's actually quieter than the Flowmaster system I had with my old TPI motor.

 

Ok. So for the most part, the headers and the holley system lined up without any cutting or anything?

The exhaust hanger mod is fine, I'm almost done fabbing my own crossmember

 

Yes. They fit like they were made to go together. Depending on how you fabbed up your crossmember it might be a little tight in that area. I simply modified my 700R4 cossmember for the 4l60e. I had to grind a few spots but it cleared fine.

 

Thanks. Good to know

 

Man, I wish someone built a system like Willie's old true dual exhaust. Exits out the left just like a SLP 2otL. I love just having the two tips on the left with my car.

But I wouldn't mind the sound of a true dual x-pipe system.

 

Ok kool. I just recently purchased the 304 version because the 409s were backordered..

I am finishing up making a custom transmission crossmember.. it's not pretty but it works

If it's not too much trouble, can you post pics of where the exhaust goes through the crossmember?

 

​​​​​​​It looks like I have to add a few inches also on the driver side. It clears the fabricated crossmember, fits on the speed engineering headers like a glove. Looks like it'll be doable

 

Did anyone do the drivers side parking cable mod that was listed in the install directions? I dont see where I will need to use the little bracket supplied in the kit. Seems it is not in the way.

 

I addressed this issue. I pretty much got the setup in except the rear mufflers. The driver side portion of the x pipe clears the drive shaft u joint, but kinda close about an 1 1/2" . Is this where you guys setup falls at?

 

Maybe because I'm using a 4th gen rear end