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Finally: Holley to produce LT and True Dual System
LTX and LSXPutting LT1s, LS1s, and their variants into Third Gens is becoming more popular. This board is for those who are doing and have done the swaps so they can discuss all of their technical aspects including repairs, swap info, and performance upgrades.
Re: Finally: Holley to produce LT and True Dual System
I ordered this system and it is truly a piece of art! The only downfall is I ordered it in Oct and just received it last week, approximately 4 mo. that is a long time to wait. So if you go to Holly website and see that they are on backorder be prepared to wait awhile. Fortunately I was planning ahead and ordered them before they were needed. I can say that it is worth the wait!! the problem is they only make so many at a time and if they are out of stock Holly waits until they have enough orders to start production again.
Re: Finally: Holley to produce LT and True Dual System
Well, I was looking at some Hooker Mid-Tube Headers, but if these will work with the Spohn Motor mounts (anyone know yet?) then I'm golden. I can't use the hooker trans cross member because I'm not using an LS 4L60E.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Ozz1967
Well, I was looking at some Hooker Mid-Tube Headers, but if these will work with the Spohn Motor mounts (anyone know yet?) then I'm golden. I can't use the hooker trans cross member because I'm not using an LS 4L60E.
I can't say if it'll work with the Spohn mounts, but I got the cross member to fit with minimal modification with the setback plates I have. I had to open the bolt slots a little more, and buy a shorter poly mount for the trans, but it worked.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Ozz1967
Well, I was looking at some Hooker Mid-Tube Headers, but if these will work with the Spohn Motor mounts (anyone know yet?) then I'm golden. I can't use the hooker trans cross member because I'm not using an LS 4L60E.
In short, probably. I have Spohn mounts, UMI solid motor mounts, and I was able to get the headers to bolt up. Extremely tight clearance and in 1 area I will need make some clearance. Keep in mind I did this on an engine stand. I have yet to see how this works in the car. I will also be trimming a few spots on the K-member for ease of installation.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by joshy1410
In short, probably. I have Spohn mounts, UMI solid motor mounts, and I was able to get the headers to bolt up. Extremely tight clearance and in 1 area I will need make some clearance. Keep in mind I did this on an engine stand. I have yet to see how this works in the car. I will also be trimming a few spots on the K-member for ease of installation.
I plan on using standard LS swap motor mounts that came from Spohn as well though after seeing these, I may scrap my plan and simply go with their whole set up. That would mean going with a new transmission though, something ive been trying to avoid.
How much difference is there in height/size compared to solid mounts? Would that give more or less room in your opinion?
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Ozz1967
I plan on using standard LS swap motor mounts that came from Spohn as well though after seeing these, I may scrap my plan and simply go with their whole set up. That would mean going with a new transmission though, something ive been trying to avoid.
How much difference is there in height/size compared to solid mounts? Would that give more or less room in your opinion?
Tbh, I'm not sure. I think I have a set of OE clams I can try. I will take a look in the next day or two.
My solid mounts and Spohn mounts were all lose. I will need to see how things change with them tightened down. Other than the one tube on that one passenger side primary, they fit really well.
Re: Finally: Holley to produce LT and True Dual System
I compared the solid mounts to the stock ls1 clams and the are really close. Granted they are a direct replacement on a 4th gen, so that would make sense.
I changed the mounts to stock LS clams and things were close, but not the same. Clearance on the passenger side seemed to get slightly better on the one primary tube as well as by the A arm mounting points. On the driverside the A arm mounting points seemed to get tighter. Slight trimming of the K by A arm mounts would go a long way. I will do this just to make things easier. 5 mins with a cut off wheel and done. Keep in mind, both times the engine mounts and k mounts were slightly loose to line everything up. I am sure this will change a tad if things were tight.
Passenger side
Driverside
Bottom line, the Spohn mounts should work with the Hooker headers. I have seen others do it as well. My main reason for using the Spohn mounts is to run 4th gen ac in stock location. If no AC or high mount AC, choose the system that fits your budget.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by joshy1410
I compared the solid mounts to the stock ls1 clams and the are really close. Granted they are a direct replacement on a 4th gen, so that would make sense.
I changed the mounts to stock LS clams and things were close, but not the same. Clearance on the passenger side seemed to get slightly better on the one primary tube as well as by the A arm mounting points. On the driverside the A arm mounting points seemed to get tighter. Slight trimming of the K by A arm mounts would go a long way. I will do this just to make things easier. 5 mins with a cut off wheel and done. Keep in mind, both times the engine mounts and k mounts were slightly loose to line everything up. I am sure this will change a tad if things were tight.
Passenger side
Driverside
Bottom line, the Spohn mounts should work with the Hooker headers. I have seen others do it as well. My main reason for using the Spohn mounts is to run 4th gen ac in stock location. If no AC or high mount AC, choose the system that fits your budget.
I'm running high mount accessories in the third gen location.
I just don't have a 4l60e (700r4) so I can't run the Holly set up with their trans cross member that I'm aware of. I'm going to contact them and see.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Ozz1967
someone on LS1Tech posted that the headers fit fine using Spohn motor mounts. I don't know what cross member he's using though.
I also want to know if using a stock dimension DS is possible. Mine is after market 3" but is a bolt in stock size.
Best to measure. I know Holley mounts slide everything forward a tad. This may be enough to make your DS too short. I know BADNBLK has a stock length DS in his car, but he has a 9 inch rear.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by joshy1410
Best to measure. I know Holley mounts slide everything forward a tad. This may be enough to make your DS too short. I know BADNBLK has a stock length DS in his car, but he has a 9 inch rear.
I was just chatting with a member over on ****** Militia Facebook page and he has this system says his stock drive shaft and 10-bolt fit fine so I think i should be ok. I guess there is only one way to know for sure though lol
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by toddoky
Hey guys. I just finished getting caught up on latest responses on this thread and thought It would be helpful to make an official technical post to clear up some of the confusion/assumptions surrounding the new Hooker 3rd-gen transmission cross member and dual exhaust system. These highlights should make things more clear to anyone reading.
1.) Both the crossmember and the exhaust system were initially developed as part of the Hooker LS swap system of parts for this vehicle application. These components and the related LS swap headers and engine mounting brackets were all developed at the same time to work as a bolt-in package with the Holley 302-2 oil pan, or any other pan that will install within the same fitment envelope.
2.) The engine/trans mating plane was moved forward in the car slightly to accommodate all transmissions we elected to provide installation of with the Hooker trans crossmember, which is the TH400, 2004R, 4L60-4L70, 4L80/4L85, 4th-gen F-body T56 and T56 Magnum. Of all these transmissions, only the T56 and T56 Magnum are installed directly on the crossmember; the other transmissions install using available adapter plates, or a spacer block between the crossmember and the trans mount (2004R and TH400).
As a side benefit, the slight forward nudge of the eng/trans mating plane also provides sorely needed clearance at the A/C evaporator case for those wanting to retain that factory piece in their car build. The engine was not moved forward an inch as I have read in this post...the eng/trans mating plane was moved slightly for the reasons stated above and the engine was placed according to that position.
For those not aware, the LS engine block is 1" shorter than a SB Chevy, so if you moved the eng/transmission mating plane forward 1" the front of the LS engine would be at the same location that the front of the original SB engine was in the car. As located with the Hooker LS swap mounting components, the front of the LS engine is set back from where the front of the SB Chevy lies in the car.
3.) In addition to its usage in an LS swap application, the transmission crossmember can be used directly to swap an LT1 T56 into a 3rd-gen behind a SB Chevy. This is possible because the location of the trans mount pad from the bellhousing mating face is 5/8" further forward on an LT1 T56 than it is on an LS T56...don't get caught up in the math, just understand that it all works our to our benefit and yours if you happen to be running, or are interested in running that eng/trans combination. With that said, the optional brackets used to mount the other transmissions in the LS swap applications are worthless in being able to mount any of those same transmissions behind a stock SB due to the mount location discrepancy between the LT1 T56 and LS T56 transmissions.
4.) The dual exhaust can be modified to connect to any set of headers as a posting member on this forum has shown to good effect. I did the same thing on the IROC test vehicle I had and adapted the Hooker dual exhaust system to a set of 2210's that were already on the car in about 4 hours. For those choosing to use the Hooker trans crossmember in a SB/T56 swap, you will be able to obtain the highest exhaust ground clearance achievable in these cars.
5.) These components aren't intended to please ever 3rd-gen owner out there and are specifically intended for those that have an appreciation for components that provide a balance of optimized fitment, power production, superior ground clearance and build quality. I don't check in here often, but I'll subscribe to this thread for a couple of weeks to hopefully be able to give you a direct answer any questions you might have about these components/systems.
6.) The crossmember does not include the torque arm bushing, it is a user-supplied part.
Would an lt1 4l60 combo work since it sits in the same spot as a sbc and a sbc works with a t56 so why not a 4l60 with correct mount.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Fbomber
Would an lt1 4l60 combo work since it sits in the same spot as a sbc and a sbc works with a t56 so why not a 4l60 with correct mount.
he doesn't know. They built the system to work with itself so if it works in another combo that's a coincidence. He's said as much several times. We're going to have to do the leg work to see what combos work with what.
Re: Finally: Holley to produce LT and True Dual System
Be careful making assumptions of fitment for combinations of components for which the Hooker components were not directly designed for. The Hooker crossmember works in an LT1 T56 swap behind a SB Chevy only because the mount on that transmission is 5/8" further forward than the mount on an LS1 T56. The Hooker LS swap engine brackets do not move the engine forward 1" as stated, they merely move the engine/trans mating plane forward by 5/8", which still places the rear faces of the LS cylinder heads further back in the car than the rear faces of the cylinder heads of a swapped out SB Chevy. This is due to the fact that the LS engine is 1-3/16" shorter on the back end than a SB Chevy engine. As an interesting side note, this is exactly the same shift in the engine/trans mating plane location GM used when they migrated to LS power in 4th-gen F-bodies.
Re: Finally: Holley to produce LT and True Dual System
toddoky
I know that this system is supposed to work with all models but I wanted to let you know that the mufflers are tucked up to high with the supplied rubber hangers to clear the and exit under the bumper for the 91-92 Firebird / Trans am ground effects. I was able to get some longer rubber hangers to make it work but it does obviously hang lower. Thanks for your hard work on this system as it fits the car very well otherwise!!
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by 91firebird5.0
toddoky
I know that this system is supposed to work with all models but I wanted to let you know that the mufflers are tucked up to high with the supplied rubber hangers to clear the and exit under the bumper for the 91-92 Firebird / Trans am ground effects. I was able to get some longer rubber hangers to make it work but it does obviously hang lower. Thanks for your hard work on this system as it fits the car very well otherwise!!
Thanks for providing that feedback. Can you post a photo of the rear bumper of your car so I can put it into my development file with some notes? If using longer rubber hangers provided the clearance you needed, you may have been able to achieve the same results by placing spacers between the formed metal hanger brackets and the frame rails.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by toddoky
Thanks for providing that feedback. Can you post a photo of the rear bumper of your car so I can put it into my development file with some notes? If using longer rubber hangers provided the clearance you needed, you may have been able to achieve the same results by placing spacers between the formed metal hanger brackets and the frame rails.
Here are a few pictures of the muffler's, hangers, and bumper.
supplied rubber hangers.
hangers needed to clear bumper.
difference between hangers.
new hangers make rear slope down hill.
supplied hangers sit nice and level but as you see wont clear bumper gfx.
Last edited by 91firebird5.0; 05-17-2017 at 08:04 PM.
Re: Finally: Holley to produce LT and True Dual System
Thanks for taking the time to post the pics...the middle one is exactly what I needed to see and tells me I'll just have to exclude the Trans AM models from being a direct fit application. I validated the system on a Z28 and a Formula Firebird, which it fits great on both of those. Unfortunately, there's no way to drop the tips enough to clear the lower valance on the Trans Am without creating too much gap between the tips and the bumpers of the other models.
Re: Finally: Holley to produce LT and True Dual System
Before I order a set of UMI motor mounts has anybody run these with a UMI k-member? I've got a road race unit and neither my Holley mounts or old Spohn mounts are going to bolt up
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by KagA152
Before I order a set of UMI motor mounts has anybody run these with a UMI k-member? I've got a road race unit and neither my Holley mounts or old Spohn mounts are going to bolt up
I reached out to Holley earlier this year... and there were no plans to make their kit work with the UMI K-Member....
Re: Finally: Holley to produce LT and True Dual System
also interested in k member option, I just purchased the engine mounts, transmission x member, plus the extension for the 4l80. I was really looking forward to replacing the stock k-member though. i would hate to go through the ls swap and keep the ugly heavy k-member. any luck with aftermarket k-members??
i was looking at spohn and they have a k member that has motor mount pad available for v6:
Motor Mount Pads: K-members are available with no motor mount pads for those who will be using a motor plate, or with mounting pads that will accept standard small block, big block, LT1 or 3.8L V-6 motor mounts.
would this be a better option than getting a LS http://www.spohn.net/shop/1982-1992-...C-BBC-LT1.html
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by CRAMOS78
also interested in k member option, I just purchased the engine mounts, transmission x member, plus the extension for the 4l80. I was really looking forward to replacing the stock k-member though. i would hate to go through the ls swap and keep the ugly heavy k-member. any luck with aftermarket k-members??
i was looking at spohn and they have a k member that has motor mount pad available for v6:
Motor Mount Pads: K-members are available with no motor mount pads for those who will be using a motor plate, or with mounting pads that will accept standard small block, big block, LT1 or 3.8L V-6 motor mounts.
would this be a better option than getting a LS http://www.spohn.net/shop/1982-1992-...C-BBC-LT1.html
Holly will never publicly admit if their system is compatible with anyone elses. That's up to us to figure out,
Re: Finally: Holley to produce LT and True Dual System
Actually, if there were aftermarket K-members that were known to us to be compatible with the Hooker swap components, we would have no problem saying so.
Why would we? If we could validate the fact they would be compatible it would mean more parts sales for Holley, which is the whole reason we come to work every day.
In the case of the 3rd-gen F-body application, I'm not aware of the existence of any aftermarket K-member that replicates the entire factory K-member engine mount hole pattern (includes V6 and V8 mounting holes), which would be required to be able to bolt on the Hooker engine brackets.
The holes used for the Hooker brackets were chosen as needed to be able to clear the cages of the 4th-gen F-body engine mount clamshell housings that the Hooker brackets are designed around.
Accommodating aftermarket K-members might be something we'll do in the future for this application, like we just started doing with our Fox body Mustang LS swap kit we're about to release. I can tell you that it is a major undertaking to do so as the aftermarket K-members move the engine position all over the place from the factory position.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by robguitargod1
Could you please sell me just the mufflers??
Pretty please??
Or maybe recommend one that's very similar?
If I had the ability to do that I would (I don't have any connection to the sales functions/activities of the company). The mufflers used in the Hooker F-body dual systems were developed specifically for those applications and are currently not available as stand-alone products...I will certainly mention in inquiry about them being available as such to the Hooker product manager.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by CRAMOS78
Toddoky, so the hooker engine mounts do not go on the v6 holes? sorry I was under that impression. and thanks for all the info....
From memory, I believe they use holes from both the V8 and V6 patterns...I wouldn't be able to say definitively without reviewing the development file.
Re: Finally: Holley to produce LT and True Dual System
Has anyone tired using the hawks t56 crossmember with the blackheart exhaust system? I know it will not have the spot for the hanger on the passenger side like the hooker crossmember does. But curious if anyone has had any success with it? I already have the blackheart headers, I just need to get some of my ground clearance back and was hoping that I didn't need to get another crossmember to make this exhaust work when there is nothing wrong with the crossmember I have.
Re: Finally: Holley to produce LT and True Dual System
Thinking of trying this crossmember with my BMR ls1 kmember/mounts. I've read that it won't work. Running a th400. Can't I just drill and tap new holes where the crossmember needs to be? Also, would this style torque arm mount with the bushing, hold up to 800rwhp and track launches off a brake? Or should I get a heim joint and mount somehow. I have a full length BMR arm now.
As for 800 rwhp launches, that kind of power will break a lot of things. I can see how the OEM "clamshell" mount would spread apart. It's happened to me but not due to HP. There are several aftermarket torque arm mounts that eliminate the factory approach. I had a Spohn heim joint style on the big block TA a few years back that was designed to work with their crossmember and a TKO transmission.
Re: Finally: Holley to produce LT and True Dual System
Anyone ever installed this system with the Hawks "budget" LS swap headers and Hawks 4L60E transmission crossmember? I already have them installed on the car. I'm wondering how much, if any, modifications would be needed. My main concern is the crossmember clearance and header output to line up with the blackheart pipe. Thanks
Re: Finally: Holley to produce LT and True Dual System
Has anyone used the listed Hooker & Holley kit, including the Holley 302-2 pan and Hooker Blackheart LS mounts, and still use the stock LS1 AC Compressor?
The Hooker Blackheart LS Mounts shift forward from the original engine location and would appear to possibly clear the K-member but perhaps not. It may still need to be notched but not like the conventional LS swap K-member notching.
Anyone tried?
Edit -
Looks like 91firebird5.0 answered my question . In case anyone else in interested, here is a good picture from his build with these mounts.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by toddoky
Actually, if there were aftermarket K-members that were known to us to be compatible with the Hooker swap components, we would have no problem saying so.
Why would we? If we could validate the fact they would be compatible it would mean more parts sales for Holley, which is the whole reason we come to work every day.
In the case of the 3rd-gen F-body application, I'm not aware of the existence of any aftermarket K-member that replicates the entire factory K-member engine mount hole pattern (includes V6 and V8 mounting holes), which would be required to be able to bolt on the Hooker engine brackets.
Accommodating aftermarket K-members might be something we'll do in the future for this application, like we just started doing with our Fox body Mustang LS swap kit we're about to release. I can tell you that it is a major undertaking to do so as the aftermarket K-members move the engine position all over the place from the factory position.
This is exactly what you should do, a tubular engine cross member that bolts to your motor mounts for this system would be amazing. Something on Par with PA Racing's Road race kit for a mostly daily driven car would be sublime. I hope you do it. Of course this means you'll need compatability with stock a-arms or other tubular styles...or build your own, muahahaha! I ccan see the $$$ flying by.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by Ozz1967
This is exactly what you should do, a tubular engine cross member that bolts to your motor mounts for this system would be amazing. Something on Par with PA Racing's Road race kit for a mostly daily driven car would be sublime. I hope you do it. Of course this means you'll need compatability with stock a-arms or other tubular styles...or build your own, muahahaha! I ccan see the $$$ flying by.
I would be game for it, but I don't see it happening as the development schedule is already locked down pretty far into the future. It would be easier for an existing suspension company to make a K-member, or a set of engine brackets for their existing K-member, that locates the engine in the same fore/aft location as the Hooker Blackheart 3rd-gen LS swap system does and advertise it as being compatible with the Hooker Blackheart swap system.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by toddoky
I would be game for it, but I don't see it happening as the development schedule is already locked down pretty far into the future. It would be easier for an existing suspension company to make a K-member, or a set of engine brackets for their existing K-member, that locates the engine in the same fore/aft location as the Hooker Blackheart 3rd-gen LS swap system does and advertise it as being compatible with the Hooker Blackheart swap system.
That would be ideal. Unfortunately yours is the only one I know of that spaces the motor as it does.
Re: Finally: Holley to produce LT and True Dual System
It would be easy enough to replicate by any company that has a digitizing arm, a stock 3rd-gen K-member and a set of our engine mounting brackets. The engine location scheme we used for the 3rd-gen system is the same as what GM used for the 4th-gen cars when they switched to LS power in 1998, which is they moved the engine/transmission mating plane forward from the previous SB Chevy location by approximately 5/8". This shows up easily when you compare the distance between the bellhousing face and the transmission mount on an LT1 T56 transmission and an LS1 T56 transmission; the measurement on the LS1 T56 is 5/8" longer than the LT1 T56. The LS block is 1-3/16" shorter than a SB Chevy block, so moving the engine/transmission mating plane forward by 5/8" from the stock SB Chevy location still places the LS cylinder heads further back in the car than the SB Chevy cylinder heads would reside and it improves transmission fitment with every GM late model automatic transmission.
Re: Finally: Holley to produce LT and True Dual System
FWIW - The Holley dual x pipe true dual 2.5 inch BlackHeart exhaust is good for at least 517 whp & 471 wtq with a good set of 1 7/8 headers. I suspect that's close to the point the twin 2.5 becomes a restriction or about ~600 flywheel.
My 4th Gen TA has the x-pipe back BlackHeart. It fit very well. No issues using the Hawk's 8.8 rear end with it. The system seemed sort of quiet at first but after 2,000 miles and some high rpm it's anything but quite now even at idle.
With the 416 LS the TA seems to get louder every time driven. I think the old SLP Dual / Dual may go back on the car with a pair of cutouts to get the exhaust quieter.
Re: Finally: Holley to produce LT and True Dual System
Hi folks,
Its just about time to get my LS1/T56 back into the car, I was wondering what everyone's preferred method was with the full Holley setup before I scratch up my engine bay unnecessarily .
I have the Holley LT headers, mounts, crossmember and 302 pan with a notched stock K member for LS AC compressor.
I had read for some LT headers mounts that it very difficult/impossible to do the whole engine/trans together through the top, but can it be done with the Holley mounts since they move forward? I think the instructions that came with the trans crossmember suggested putting the engine in first and then bringing the T56 underneath, but I believe this would require balancing the LS 1 with just the two K member mounts which sounds a little tricky. I believe I also need to do a 3/4" deep notch on the rear side of my original T5 shifter hole in order to line it up properly . Does anyone have any pictures of this to share?
I would prefer to do drop the whole assembly in together but can anyone confirm it can be done this way? If so, is it worth the time to remove the front clip for ease of lining up? Car is being done with a couple of jacks and stands - no lift for me.
Re: Finally: Holley to produce LT and True Dual System
Originally Posted by toddoky
It is a good skill to have for sure. I think I'm fairly certain about the major cause of the non-compatibility you're experiencing between the crossmember and your BMR subframe. The Hooker engine brackets and crossmember work in tandem to place the LS crankshaft and transmission centerline axis in the same location as the stock SB engine and transmission was set up with. If the BMR subframe moves the engine up and/or back, then it will cause you to have to drop the tail of the transmission down from the stock position to enable the top of the trans to continue to clear the trans tunnel/firewall sheet metal. The only way to prevent that would be to cut open the tunnel and rebuild it around the transmission. I believe this to be the case in your situation due to the interference you are experiencing between the crossmember and the reverse lockout solenoid; there is no such interference when using the crossmember with the Hooker engine brackets, even with the torque arm bracket set to the highest set of holes as you see in my mock-up photos.
" The Hooker engine brackets and crossmember work in tandem to place the LS crankshaft and transmission centerline axis in the same location as the stock SB engine and transmission was set up with."
Ok, so my ls swap 4.8/4l60e uses setback plates and originally 350 motor mounts that places the engine/transmission in the factory location to where I am using the factory drive shaft & torque arm mount location. Is there a good chance that this crossmember will fit?
02-06-2017, 11:00 AM
I hope you do it. Of course this means you'll need compatability with stock a-arms or other tubular styles...or build your own, muahahaha! I ccan see the $$$ flying by.
