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Guys, Im new and have read the entire post, but I can't figure out why you couldn't or shouldn't run the LS pressure plate and change your TOB instead of taking a chance on reaming the BBC pressure plate out to much and getting it out of balance. I am putting a 2001 LM7 5.3L in a 1980 Jeep CJ5. I am going to run a 621 bellhousing with an 11" clutch setup. My Tranny is a Ford T18. The centering hole in the 621 mates up with my Bearing retainer, and i can do the modifications required to bolt up the Tranny, but I cant find why everyone uses the BBC pressure plate when bolting up to an old school 4 Speed. Any help would be greatly appreciated.
Thanks again.
I believe it has to do with the stack up height of the pressure plate and throw out bearing. You need the right clearance otherwise the clutch will not release.
If you go back a few posts where the guy had the issue with his clutch engaging abruptly, it was due to over-centering of the fingers when using another pressure plate. That's the one side of the extreme. The other side is not enough actuation and the clutch won't disengage. Of course this may be remedied with adjustable throw out bearings or different length versions.
A lot depends on the spline count of your input shaft and what the disk will work with. There can be interference issues mixing and matching flywheels, pressure plates, and disks. Not just a question of TOB depth. I put 2 different throwout bearings that can be used with the LS1 flywheel/pressure plate, vs the truck flywheel/BBC pressure plate in my first post.
BTW, not familiar with that trans, but most ford trans I've seen have a longer input shaft with different diameter to GMs. Also larger pilot bearing and different trans input shaft bearing retainer diameter.
The Ford T-18 has a 1 1/16" 10 spline instead of the 1 1/8" 10 spline input shaft, so i have to use an 11 Clutch disk that matches the ford pattern. Novak makes a pilot bushing that works in the LS with the ford input shaft. They also make a Bearing retainer that mates up to the 621 bellhousing and lets me use a chevy TOB. The Stickout length on the t-18 is 6 1/2" so it will work with my 621 bellholusing. Novak sells an adapter Flywheel for the LS motor that uses the 3/8" shoulder bolts for the SBC, and offsets the needed .400" for the crank difference, But i would rather not drop $360 on a flywheel if i can get a $60 flywheel to work with a little bit of research and effort.
So I think i am going to get the Sachs 1050 flywheel and try the SBC pressure plate. If novak says it will work with the Ford disk and their adapter flywheel, it should work with the 1050 flywheel if i can keep it centered.
Did I miss anything?
I know there are a few guys over at the C3 corvette forum using the 11" clutch pressure plate and a ford disk with ford T5s, so it might work.
So if I got this right, adapter pilot bearing and GM input bearing retainer. Sachs 1050 flywheel, GM 11" pressure plate, ford disc....let us know if it works.
BTW how do you match up the bell to trans different Ford vs GM bolt pattern?
Also. I have a Sachs 1050 flywheel and Chevy 11" flywheel and both 10 and 26 spline disks if you need any measurements.
Originally Posted by gatorgabe
The Ford T-18 has a 1 1/16" 10 spline instead of the 1 1/8" 10 spline input shaft, so i have to use an 11 Clutch disk that matches the ford pattern. Novak makes a pilot bushing that works in the LS with the ford input shaft. They also make a Bearing retainer that mates up to the 621 bellhousing and lets me use a chevy TOB. The Stickout length on the t-18 is 6 1/2" so it will work with my 621 bellholusing. Novak sells an adapter Flywheel for the LS motor that uses the 3/8" shoulder bolts for the SBC, and offsets the needed .400" for the crank difference, But i would rather not drop $360 on a flywheel if i can get a $60 flywheel to work with a little bit of research and effort.
So I think i am going to get the Sachs 1050 flywheel and try the SBC pressure plate. If novak says it will work with the Ford disk and their adapter flywheel, it should work with the 1050 flywheel if i can keep it centered.
Did I miss anything?
With the adapted bearing retainer centering the transmission, the top two holes in the T-18 are are low by about 1/8" you can elongate these two holes and get them to mate up. In the location of the driver side bottom bellhousing hole, there is a machined boss in the T-18 without a hole that can be drilled to match the bell. for the passenger side bottom you have to drill the boss and drill and tap the Bellhousing. The factory ford bottom holes are much lower than the Chevy pattern.
It will be a few weeks before i get to work on this, I live in Louisiana, but work in Canada. I will let everyone know how it turns out!
Originally Posted by garys 68
I know there are a few guys over at the C3 corvette forum using the 11" clutch pressure plate and a ford disk with ford T5s, so it might work.
So if I got this right, adapter pilot bearing and GM input bearing retainer. Sachs 1050 flywheel, GM 11" pressure plate, ford disc....let us know if it works.
BTW how do you match up the bell to trans different Ford vs GM bolt pattern?
Also. I have a Sachs 1050 flywheel and Chevy 11" flywheel and both 10 and 26 spline disks if you need any measurements.
Garys68,
I want to thank you and the rest of the folks that have made a engineering project much easier today than when I started this thread a few days ago.
I now have the option of placing the Muncie back in my 62 Corvette with a new SRlll tube chassis and a 5.3 LS engine
I'm using the short pivot ball. I've done everything to the letter per the beginning of this post. I'm not getting whats up with mine. Last time I did an auto to stick conversion was in like 1984, when you could get all original stuff from the bone yard off the exact same car. That was nice. And yes, used to be a ton of 70-72 Chevelles in the yards back then.
I am currently building an LQ4 that I will bump the compression up to 10.5:1 to 11.1:1 using different pistons and heads. This will be going in a 68 Firebird and I want to keep the nostalgic 4 speed. I have read thru this thread and I think I have all the items identified to buy to keep the Muncie. However, I noticed the thread was created a few years back and there are only a few recent posts on the thread. So I wanted to touch bases to see if there were any new lessons learned and finalize my decision.
Right now I see the LS flywheel causes issues with the distance it reaches from the crank at .4" short. I see McLeod has resolved this by creating a .4" thicker flywheel, but it is $400+. The Sachs flywheel is only $70. Are you comfortable with the clutch disk not seating on the transmission input shaft all the way or would you be more comfortable with the thicker flywheel and correct fitment of the clutch disk?
I am not sure I understand the dowel pin removal requirement on the Sachs. Can you explain?
I was considering an High Performance Clutch Kit like http://www.summitracing.com/parts/ct...5552/overview/ but I am not seeing a way to verify fitment to the Sachs Flywheel. Any thoughts or advice to a clutch kit to use?
First off are you using a 10 or 26 spline Muncie?
Second, I'm still around.
Third, no one I know of has had issues with 0.4" spline engagement. I think you need to re read this though. Regardless of clutch, the input shaft is engaged through the entire pilot bearing. It's only with an f body flywheel (can be used with 26 spline), the end of the disk splines run off the end of the input shaft. The sachs flywheel (used with 10 or 26 spline shaft) is 0.4" thicker, so that's not an issue.
The sachs flywheel is actually for a 12" 05 truck clutch. Dowel pins are for that. The pressure plate drill pattern is the same as a 60/70s bbc 11" clutch, which doesn't have dowel pins.
Cant comment on aftermarket clutches. There's an exaple of a mix and match that didn't work in this thread, and one that did.
I have to separate the trans from the current motor yet so I am not sure which spline it has. I suspect it will be the 10 spline since it is supposed to be the factory transmission for the 68 Firebird. I understood the input shaft was engaged in the pilot bushing. My concern was targeted at the disk to shaft relationship, which you point out no one has had an issue. Just wanted to see if there was any follow up to that, which you also have clarified. On the down pin removal. Is the down pin there to clutch to the flywheel or is it there to align the flywheel to the crank?
There are 2 pins on the sachs flywheel to align the pressure plate. There are holes for them on the truck PP, but not on the BBC 11" PP.
On my clutch, 3 of the holes in the pressure plate were too small for the bolts. I only enlarged them enough to get the bolt through, hopefully centering it correctly. I ran it for years like that, no issues. If I had to do it again, I would probably confirm balance with a machine shop.
BTW, there's also pin holes in the crank and flywheel for a pin, but none there or needed.
The one thing nobody has offered any solutions for is exhaust. I have two sets of headers, neither clear the mechanical linkage. Truck manifolds are don't work well in a Chevelle. What are you mechanical linkage guys using?
on my 68 corvette, I'm running corvette 02 Z06 stock manifolds. Clears the Z bar and flows better than most headers.
The stock 98-02 F body will also clear the bell mounted stud for mechanical linkage.
Also note that the 3 f=different types of motor plate adapters will move the engine relative to the frame Z bar mount location.
Originally Posted by 71buickfreak
The one thing nobody has offered any solutions for is exhaust. I have two sets of headers, neither clear the mechanical linkage. Truck manifolds are don't work well in a Chevelle. What are you mechanical linkage guys using?
I have another questions. At the beginning, there are some part numbers listed that I am not sure whose part numbers they are. For instance, pressure plate bolts and flywheel inspection covers. Are they GM numbers?
Those are all GM numbers.
The Sachs flywheel is a sachs number. You should be able to find at any parts store.
Originally Posted by farmall
I have another questions. At the beginning, there are some part numbers listed that I am not sure whose part numbers they are. For instance, pressure plate bolts and flywheel inspection covers. Are they GM numbers?
Has anyone measured the distance of the area of the disk splines that do not contact the input shaft on the tranny when using the shallower ls1 flywheel? The total length of the disk splines is around 1.5", how much of it is left past the splines of the input shaft? 1/4, 1/2"?
When using the thicker sachs flywheel and an 11" disk how much of the disk width does not actually contact the machined friction surface of the flywheel?
Does anyone know the over all length difference with a 621/685 bell of a muncie vs a t56 with a stock bell?
Does using the larger truck bell housing allow the use of the larger disk and therefore a larger pressure plate solving the issue of the 11" disk not completely mating to the flywheel?
This info is whats keeping me from selling my t56 and swapping in a muncie 4spd.
06-10-2015, 01:52 PM
Whats the Difference in the Pressure plates 
