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So... i have a GMMG exhaust system. Long story short i traded some parts locally and got my hands on a cheap Hooker blackheart exhaust brand new in the box.
Stock l98, and I will be running Dougs headers and high flow y pipe. Which exhaust would you run? The Hooker blackheart is a direct bolt on kit that directly connects to the dougs y pipe. If I run the GMMG then I will have to have an intermediate pipe fabbed together.
On a stock L98? Neither. Borla or Magnaflow might be my 'today' choice. I love the gmmg, but I'd want it on something with a little more cam and more rpm. I'd love a gmmg now but they went out of stock last I saw.
Where's the BlackHeart exhaust in all of this? I see Hooker which doesn't necessarily translate in to the BlackHeart brand.
This is the BlackHeart system that I've been looking at.
I sold my GMMG exhaust and regret it all the time. It sounded amazing with SBC.
Originally Posted by blacksunshine'91
IMO, the GMMG is hands down the best sounding exhaust on thirdgens that I have heard..
What mufflers are in that GMMG kit?
I'm looking for a small diameter muffler (as in overall diameter but a 2-1/2" I.D. minimum) to hang off the ends of my headers. More of a race deal than anything else and a step short of track day open headers, which would still require some kind of collector extension. The right muffler, like a glasspack or similar can be used as that extension if you're going for tuned length.
I can't say I like how the GMMG kit has a 180° bend into the 2nd muffler but, I think that could remedied by fabricating a 1 into 2 split before the mufflers and then exit with two on the left.
At least the problem of CFM capacity is likely overcome seeing as it's very difficult to find a single muffler with 900 CFM of flow that won't split your ears! Maybe a bump up to a 3-1/2" intermediate pipe would help too.
There's going to be some minor fabrication required no matter which combination you choose. Are you planning to keep the cat or delete it? It's 3". And is the 2.75" factory intermediate pipe still good?
Doug's Y-pipe has a 2.5" collector. The Hooker cat-back is 2.5". I believe the GMMG is supposed to be 3" over the axle.
You can modify the Y-pipe's collector to 3" at the merger of the Y and run a 3" pipe to the cat, or you could chop a bit off the end of the 2.5" pipe and put a 2.5" to 3" reducer so the cat will slip into it. Then instead of having a new intermediate pipe made, cut your factory 2.75" intermediate pipe where it needs to connect to the GMMG.
With the Hooker, you'd have to do the same modification to the Y-pipe so it fits the cat. Then you could chop off the front of the Hooker 2.5" intermediate pipe at the cat, also chop off the same length of the front of your factory intermediate pipe, then put the factory end onto the Hooker pipe, but you'd still have downsized to a 2.5" exhaust system from front to back. Or keep the factory intermediate pipe here too and make the modification where it connects to the Hooker muffler.
So if your factory intermediate pipe is usable, then neither system will be too complicated to install. It will make the Hooker exhaust a little better than Hooker made it. But I think you'll have a better exhaust system with the GMMG.
There's going to be some minor fabrication required no matter which combination you choose. Are you planning to keep the cat or delete it? It's 3". And is the 2.75" factory intermediate pipe still good?
Doug's Y-pipe has a 2.5" collector. The Hooker cat-back is 2.5". I believe the GMMG is supposed to be 3" over the axle.
You can modify the Y-pipe's collector to 3" at the merger of the Y and run a 3" pipe to the cat, or you could chop a bit off the end of the 2.5" pipe and put a 2.5" to 3" reducer so the cat will slip into it. Then instead of having a new intermediate pipe made, cut your factory 2.75" intermediate pipe where it needs to connect to the GMMG.
With the Hooker, you'd have to do the same modification to the Y-pipe so it fits the cat. Then you could chop off the front of the Hooker 2.5" intermediate pipe at the cat, also chop off the same length of the front of your factory intermediate pipe, then put the factory end onto the Hooker pipe, but you'd still have downsized to a 2.5" exhaust system from front to back. Or keep the factory intermediate pipe here too and make the modification where it connects to the Hooker muffler.
So if your factory intermediate pipe is usable, then neither system will be too complicated to install. It will make the Hooker exhaust a little better than Hooker made it. But I think you'll have a better exhaust system with the GMMG.
Shall I assume you're referring to the OP rather than my more specific question?
There's going to be some minor fabrication required no matter which combination you choose. Are you planning to keep the cat or delete it? It's 3". And is the 2.75" factory intermediate pipe still good?
Doug's Y-pipe has a 2.5" collector. The Hooker cat-back is 2.5". I believe the GMMG is supposed to be 3" over the axle.
You can modify the Y-pipe's collector to 3" at the merger of the Y and run a 3" pipe to the cat, or you could chop a bit off the end of the 2.5" pipe and put a 2.5" to 3" reducer so the cat will slip into it. Then instead of having a new intermediate pipe made, cut your factory 2.75" intermediate pipe where it needs to connect to the GMMG.
With the Hooker, you'd have to do the same modification to the Y-pipe so it fits the cat. Then you could chop off the front of the Hooker 2.5" intermediate pipe at the cat, also chop off the same length of the front of your factory intermediate pipe, then put the factory end onto the Hooker pipe, but you'd still have downsized to a 2.5" exhaust system from front to back. Or keep the factory intermediate pipe here too and make the modification where it connects to the Hooker muffler.
So if your factory intermediate pipe is usable, then neither system will be too complicated to install. It will make the Hooker exhaust a little better than Hooker made it. But I think you'll have a better exhaust system with the GMMG.
the hooker actually necks down to a 2.5 at the Catalytic converter.
Car had no cat on it when I bought it. And I wasn't planning on running one to be honest.
I was actually thinking of using the GMMG in combination with the intermediate pipe from the hooker system.
Where's the BlackHeart exhaust in all of this? I see Hooker which doesn't necessarily translate in to the BlackHeart brand.
This is the BlackHeart system that I've been looking at.
my mistake, I thought it was considered a hooker blackheart.
It's just a clarity thing.
The whole Blackheart deal came in like gangbusters and the Holley engineer, or former engineer I should say, was a frequent contributor in this forum and elsewhere.
Good luck.
