lt1 t56 to ls different conversion option
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
Nope. Flywheel needs to match the engine. You can use a bbc bellhousing but not flywheel.
TECH Regular
Joined: Mar 2015
Posts: 487
Likes: 10
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
The Sachs 1050 flywheel that thread talks about is still an LS flywheel for 4.8/6.0, so it does match the engine. The ring gear it's 12" and 168 tooth though, with a 12.6 bolt circle. The LT1-t56 uses a 153 tooth 11" flywheel (probably because of the bellhousing clearance) with an 11.6 bolt circle. The LS1 flywheel is also 12"/12.6 and 168 tooth. So I don't see a way to make this work, other than cutting up an LT1 bellhousing and redrilling a flywheel.
I'll be happy to be proven wrong, but unfortunately I don't think I am.
I'll be happy to be proven wrong, but unfortunately I don't think I am.
TECH Regular
Joined: Mar 2015
Posts: 487
Likes: 10
I guess I am confused why it won't work then?
BBC Bellhousing - Bolts to LT1 T56 case as well as the LS engine and has clearance for the larger flywheel
Sachs 1050 - Bolts to LS crank, spaces out to match BBC bell extended length, accepts LT1 input shaft sized pilot bearing
LS1 26 spline clutch - Should be .400" off the splines but apparently works that way, I would assume both t56s use the same OD 26 spline (I do not know that for a fact)
The only thing I can't figure out from the thread is which starter, I would say an LS starter and then the bellhousing may have to have a hole cut in it to fit but not sure. Since the LS is push style clutch you would need the Mcleod slave and bearing mentioned in this thread here : https://ls1tech.com/forums/manual-tr...ulic-swap.html
The BBC bell won't have the hole for a hydro line for the slave either but that is easily added.
What about the won't work? I am not being argumentative, just can't find an issue with what I just listed.
BBC Bellhousing - Bolts to LT1 T56 case as well as the LS engine and has clearance for the larger flywheel
Sachs 1050 - Bolts to LS crank, spaces out to match BBC bell extended length, accepts LT1 input shaft sized pilot bearing
LS1 26 spline clutch - Should be .400" off the splines but apparently works that way, I would assume both t56s use the same OD 26 spline (I do not know that for a fact)
The only thing I can't figure out from the thread is which starter, I would say an LS starter and then the bellhousing may have to have a hole cut in it to fit but not sure. Since the LS is push style clutch you would need the Mcleod slave and bearing mentioned in this thread here : https://ls1tech.com/forums/manual-tr...ulic-swap.html
The BBC bell won't have the hole for a hydro line for the slave either but that is easily added.
What about the won't work? I am not being argumentative, just can't find an issue with what I just listed.
Last edited by Teddy-2000RS; Aug 12, 2021 at 10:16 AM.
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
This was still bugging me, so I looked up an old 1970 Chevelle BBC clutch and see that they use an 11" disc, but still a 168-tooth flywheel and 12.6 pressure plate bolt spacing. So that's starting to make sense. It's just not any help with the small bell LT1 style T56...
A 1970 Chevelle SBC clutch uses a 10.5 disc and 153-tooth flywheel. So it looks like that's where the SBC/BBC spec comes in, because most SBC got the 153 tooth flywheel, and BBC and LS are always 168 tooth. Also why the guy specs a BBC bell housing for the LS flywheel.
A 1970 Chevelle SBC clutch uses a 10.5 disc and 153-tooth flywheel. So it looks like that's where the SBC/BBC spec comes in, because most SBC got the 153 tooth flywheel, and BBC and LS are always 168 tooth. Also why the guy specs a BBC bell housing for the LS flywheel.
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
Haha, we're both posting/researching at the same time.
The BBC bellhousing won't bolt to a T56. And the T56 input shaft is also shorter...requiring the shorter and different bolt pattern bellhousing.
The BBC bellhousing won't bolt to a T56. And the T56 input shaft is also shorter...requiring the shorter and different bolt pattern bellhousing.
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
The LT1 is a weird bastard-child spec that doesn't really interchange with anything. I had to get an expensive conversion flywheel from SPEC with a pull-style clutch to retain the stock style bellhousing for use with my 2-pc rear main seal early SBC.
TECH Regular
Joined: Mar 2015
Posts: 487
Likes: 10
This is wicked expensive IMO (compared even to swapping lt1 to ls1 input shafts) but it would allow you to use the setup I mentioned above.
https://americanpowertrain.com/shop/...ncie-t10-bell/
I did not realize the BBC bell did not bolt to LT1 t56. I had made the assumption they had not swapped trans patterns but they did obviously.
IF you had access to a mill you could make that plate super easy or mill down the BBC bell , weld a plate, then drill it for the LT1 pattern and use a conventional clutch setup. We likely would not be having this conversation if you did though haha.
https://americanpowertrain.com/shop/...ncie-t10-bell/
I did not realize the BBC bell did not bolt to LT1 t56. I had made the assumption they had not swapped trans patterns but they did obviously.
IF you had access to a mill you could make that plate super easy or mill down the BBC bell , weld a plate, then drill it for the LT1 pattern and use a conventional clutch setup. We likely would not be having this conversation if you did though haha.
Last edited by Teddy-2000RS; Aug 12, 2021 at 10:35 AM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
Five Reasons the Camaro Was the Most Pivotal Player in the Pony Car Wars 2.0
Brett Foote
10 Reasons the LS7 Is GM's Most Extreme Naturally Aspirated V8 Engine Ever
Verdad Gallardo On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
Hmm. I wonder why that exists? I'm quite sure the LT1 T56 input shaft is shorter than old school stuff.
I do have a mill at work, but for the short input shaft of the LT1 T56 to work, you need to run that pull clutch because there isn't room for a traditional one.
I do have a mill at work, but for the short input shaft of the LT1 T56 to work, you need to run that pull clutch because there isn't room for a traditional one.
On The Tree
Joined: May 2021
Posts: 113
Likes: 78
From: Walton NY
Nvm, I re-read that. Comes with another input shaft (probably just the LS one). I know guys on NastyZ used to use an LS T56 and adapter to run a traditional clutch and flywheel behind SBC/BBC. So this is basically converting an LT to LS T56 to do the same thing. haha
TECH Regular
Joined: Mar 2015
Posts: 487
Likes: 10
In the link I listed in post #24 it says that Mcleod makes a short slave/TOB that fits a LT1 length input to be used with an LS style clutch. I would imagine that adapter exists so those putting a t56 behind a SBC/BBC can retain there current clutch/flywheel setup but not sure.
