86Base

iTrader: (2)

I'm looking for an exhaust for my 383 stroker going in. I found this Hooker Blackheart dual over axle exhaust and was looking at getting it. The question is I see that this exhaust is primarily used with ls swaps, can I use this behind my sbc with longtube headers? I know there will be some minor modification, I have a bmr th350 transmission crossmember and I will have to fab the exhaust from the headers past the crossmember and tie it into the exhaust. Are there any potential issues? I only need the exhaust to work from the transmission crossmember back.

toddoky

As you are willing to take care of providing connection to your headers and compatibility with your BMR crossmember, it will work great for you. I easily adapted the system to a Holley employee's SB powered 3rd-gen a couple of months ago with good results.

RamIt

Toddoky, would it be possible to get a sound clip of said employee's car?
I have been curious to hear a 3rd gen with this setup,

toddoky

I believe I can pull something together next week if the weather cooperates.

86Base

iTrader: (2)

Yes that's the fabbing I was talking about. I was thinking of just altering the front 2 pipes to go over the bmr crossmember and adapt to my headers. I'll I needed to know is if the rest of the exhaust is a straight bolt in

TORN

iTrader: (17)

I might have to dump my Magnaflow 3inch for this setup to run on my 421

http://ls1tech.com/forums/conversion...m-preview.html

86Base

iTrader: (2)

Do it. I ordered it yesterday and it's on its way. 853 with tax free shipping

Lurbie

iTrader: (3)

Is a dual 2.5" large enough to accommodate a 383 or 421 engine?

86Base

iTrader: (2)

I'm personally going to run it on my 383. Dual 2.5 should be just fine

TORN

iTrader: (17)

It's an age old question most will say no but 2x2.5 is the same as a single 3.5 inch as gases cool u need less size so I am going to give up the 5 - 10 HP to not have to build a custom pipe.

Lurbie

iTrader: (3)

I want to start out by saying, I'm not arguing, I just want to make a wise decision. I agree, it will work, but how much HP and torque change do you effect by choosing a smaller diameter? If most 383 engines should make 450-500HP (desktop dyno indicates mine should be at 500HP and Torque) and most charts I can find show anything over 400HP needs dual 3" minimum, wouldn't it cause a much larger loss than 5-10HP? I've also read, and this makes sense to me, that cold air is denser, and denser is heavier, so having your exhaust gases cool as they travel the pipe just makes it harder to push the longer the pipe/cooler the gases get, correct?
I expect I'll be spending the same amount of money or more to have a 3" dual system fabbed up for my car. If this will really support a 500HP/Torque setup, I'd rather buy this and bolt it up. I'd also have to do some basic fab to connect to my non-LS engine, but I agree with everyone that it could be done easily.

TORN

iTrader: (17)

Nope I am open to friendly conversation. I wanted to run a single 4 inch but my engine builder is fighting me tooth and nail about it being too big. So I figured 3.5 would meet in the middle. They don't make it. So Dual 2.5 = 3.5 single is next best thing. He's a racer and has built many motors so I'm going to rely on his knowledge. I have seen the effects of too big of a exhaust pipe on Harley's first hand. I help a friend of mine tune EFI Harley's all the time. It can definitely hurt the motor if you open them up too much.

86Base

iTrader: (2)

I'm in the same situation as you. My 383 is close to 580hp. All the charts I've seen show the dual 2.5 supports close to 500hp. I'm just going to with this. I guarantee you won't see much difference (2.5" to 3"') if at all except for sound

86Base

iTrader: (2)

I'm also fabbing it for a non ls engine. I figured this would be the less painful route. A mild steel custom system is close to $800 here

86Base

iTrader: (2)

Hey Torn, have you seen the mufflex systems? They have a single 3.5 to dual 3" out the back and everything in between

TORN

iTrader: (17)

Yea I have, more money and some people don't like the muffler so they end up changing it out. Also if memory serves me its not stainless steal.

Lurbie

iTrader: (3)

Just more proof that what we see on the internet isn't always true since you've seen charts showing near 500 and I had seen charts showing near 400. It's frustrating trying to find the right mix with so much misinformation. Hopefully toddoky can chime in on how this system was designed. I think that would help us a lot to hear it from the manufacturer what they designed it for. I think I read in another thread, or possibly the LS1 forum that they chose 2.5" for size and fitment of the majority of these cars.

toddoky

A dual 2.5" system can realistically be considered for any naturally aspirated application up to 450 HP (LS3 C6 corvettes produced 430HP through dual 2.5" exhaust and NPP mufflers) and even higher with forced induction. If you are going past 450HP, you should realize that at that point you will begin giving up some top end power on a progressive scale as your power level increases beyond that point.

The Hooker Blackheart dual system was designed to strike a balance of performance, sound, ground clearance, build quality and cost that is hard to beat at this point in time.

Are there systems available that will produce more power on a 500HP-up car? It is entirely possible that a single 4" exhaust may or a dual 3" system will, but they will also possess one or more of the following attributes that some users will find useful in making their purchase decision...higher cost, less optimized fitment, less ground clearance, aluminized steel construction, louder interior and exterior sound level and interior drone. If you are an individual who does not find any of these characteristics to be negative, and are strictly concerned with producing the absolute highest dyno numbers possible, then an alternative system my be a better option for you if you are running a package making north of 500HP.

Lurbie

iTrader: (3)

Thanks toddoky! I knew you'd be able to add some insight into the discussion. I appreciate you joining the forum to help answer questions on the product.

Tibo

iTrader: (15)

http://www.exhaustvideos.com/faq/how...pipe-diameter/

That is the best article I've found for exhaust diameter guidelines. They show that a dual 2.5" system should handle up to 463 and a 2.75" dual system should be good up to 566 flywheel horsepower. It's also been tested in enough articles that slightly smaller is better than slightly bigger. Dual 2.5" or single 3.5" should be fine for up to 500 hp.

Dueling73s

iTrader: (4)

First I want to thank Hooker for developing products for this car! I am currently fitting up the T56 version of the Blackheart system to my IROC with 406 SBC with TKO trans with the Hawks headers and home made cross member. If it were not for the collectors size on my headers I believe the Blackheart system would bolt up with "no" modifications. Now perhaps some optional rolled or double wall tips and the system would be perfect. I just wish the system came out a couple years ago so I would not have spent so much time building my own system.
Thanks Again!

toddoky

I'm glad to hear your install went so well, thanks for sharing your experience.

Lurbie

iTrader: (3)

A friend shared this link with me today

https://youtu.be/_PVXvHkr-Vs

It is similar to what Desktop Dyno shows for my build and that I would lose more than a few HP / Torque to a smaller exhaust system. I guess I will have to go bigger for my car.

TORN

iTrader: (17)

Sure wish they would have installed a cross or X pipe. Because it's not apples to apples. More then once people have said that will help with flow also.

Lurbie

iTrader: (3)

That's a good point. I understand that a H or X pipe also helps reduce noise.

83RDRACR

I just finished helping 86base install the Blackheart system on his car. While the back half of the kit fit like a glove and was excellent quality, because he runs a sbc and th350 we had to fab everything forward of the over the axle pipes. Running the shorter th350 allowed us to make the pipes off the headers run along side the trans and then OVER the BMR x-member. The mid pipes were made from straight sections of 2.5" pipe and tucked up real nice after some massaging of the right side rear floor pan along the tunnel. The exhaust sits up higher than his sfc's.

Maybe 86base could post some picks and audio. It sounded pretty good with the big lumpy cam he is running.

crazynights

iTrader: (3)

Would like to see pics as I also have a T350. I'd like to install the BMR cross/t/a. Also would like to see the mods to hook up to the Long Tubes.

86Base

iTrader: (2)

Sorry for the delayed response. I will get the car back up on ramps and get some pics up this weekend. I have been test driving the car the last couple days. I just broke a couple wheel studs so I will have time to get some pics. I'm not sure how I can put up a video of the exhaust but I will figure it out somehow

TORN

iTrader: (17)

Post it to You tube and link it here.

86Base

iTrader: (2)

TORN

iTrader: (17)

I would also like to see some underside shots if its not to much trouble.

Sounds great by the way.

crazynights

iTrader: (3)

Wow does that sound good!! If it isn't too much trouble would also love to see some underneath shots. Very curious how it was done to the L/T and then the Y. Thanks

86Base

iTrader: (2)

I will try to get it on the ramps today and get under it to get some pics.

Lurbie

iTrader: (3)

I look forward to seeing that also.

86Base

iTrader: (2)

86Base

iTrader: (2)

86Base

iTrader: (2)

86Base

iTrader: (2)

86Base

iTrader: (2)

86Base

iTrader: (2)

Tibo

iTrader: (15)

Do you have a tear in a frame rail by where the front of the sub frame connector attaches on the passenger side?

86Base

iTrader: (2)

I think I see what your talking about. No it's a weird angle of the photo of the hole in the frame rail that's elongated. This car was totaled and put on a frame rack

crazynights

iTrader: (3)

Wow!!! Looks AWESOME!!! Love how it's put through the crossmember instead of around or below. Does it bang/vibrate or hit anything?

86Base

iTrader: (2)

Thanks, Yeah Dave did a great job. no vibrations. I had some thick rubber belt laying around and put some piece in between the pipe and heat shield over the axle because it was really close. other than that it is great. I can now lower my car without worrying about exhaust clearance.

Tony V

iTrader: (5)

I get that everyone's into the fit of this exhaust system. But this cross member is pure stinking genius!!!!

https://www.holley.com/products/ls_p...ts/71222005HKR

toddoky

It does offer a lot of features, as long as it's used as intended and not as a universal-fit part.

Tony V

iTrader: (5)

From what I've read it works with gen I sbc and 2210's.

toddoky

It can be used to swap an LT1/LT4 T56 into SB Chevy applications, or with the Hooker 3rd-gen engine brackets to swap an LS/T56 combo into a 3rd-gen. I did install the Hooker crossmember and dual exhaust system on another Holley employee's SB/T56 equipped 3rd-gen that had 2210HKR headers on it and everything fit awesome after I modified the inlet tubes of the exhaust to fit up to the header collectors.

crazynights

iTrader: (3)

I'd buy that crossmember in a second if it could work for a T350 or 700R4. It's only for a T56. Hopefully if there is enough demand maybe Holley or another company will start producing.
I also find it odd that Holley does not make this Blackheart exhaust to mate to their own header product, 2210. But, that doesn't seem to be to much of a problem to make the exhaust work with a collector.

toddoky

The crossmember is only usable for a LT1/LT4 T56 swap in SB equipped 3rd-gens, but it can be used to install a 4L60-4L70, LS T56,T56 Magnum, TH400, 2004R or 4L80/4L85 in 3rd-gen LS swap applications, which is what it was primarily designed for.


The Hooker 2210 headers do not provide the build/fitment characteristics required to be associated with the Blackheart product line, which is why no direct connection to them was made with a specific version of the Blackheart dual exhaust system.


A new set of headers will need to be designed from scratch in the future if we choose to add a direct-fit SB header option to the Blackheart 3rd-gen applications.