[JSchmitz]

I have a TH400 and M20 that I swap back and forth with the same driveshaft. They take a different yoke because of the output shaft difference. Some yokes are "flat" or "square" and some have an offset more like a "Y". It's another detail that can affect the required length.

[nhcd538]

Is there a concern about flywheels being properly balanced? Once again I'm not sure what this 400 motor is out of or what was originally behind it. If this is an "automatic" motor (hopefully with the crank drilled anyway) will I need a specific flywheel? Am I making this too complicated? Haha.

[nhcd538]

Originally Posted by JSchmitz

I have a TH400 and M20 that I swap back and forth with the same driveshaft. They take a different yoke because of the output shaft difference. Some yokes are "flat" or "square" and some have an offset more like a "Y". It's another detail that can affect the required length.

I assumed that was the case. A fraction of an inch difference shouldn't call for a new driveshaft in my experience.

Would this yoke work? If so, what does this "type" of yoke implicate as far as length of the driveshaft?

https://www.ebay.com/itm/162598893087

[nhcd538]

Can anyone tell me if I should be looking at a flat diaphragm or a raised diaphragm clutch? I'm looking at basic Luk 10.5" clutch kits but they offer both styles.

The raised diaphragm fingers use a shorted throwout bearing and the flat diaphragm fingers use a longer throwout bearing.

Seriously WTH? Why offer both kinds, there must be a reason! I'm in for quite an education with this thing.

And while I'm at it, how do these cars like the throwout bearing to ride? Lightly pressed up against the clutch fingers or with a small air gap?

[lust4speed]

I just checked my '67 service manual and they have lengths listed. 1967 GTO manual driveshaft listed at 60" and T400 driveshaft is listed at 59.34" so the difference is .66" which is more than I thought I measured way back when. Anyway, my car came with the Muncie and I swapped to the T400 all the years I drag raced it and never had a problem just swapping yokes.

[nhcd538]

Originally Posted by lust4speed

I just checked my '67 service manual and they have lengths listed. 1967 GTO manual driveshaft listed at 60" and T400 driveshaft is listed at 59.34" so the difference is .66" which is more than I thought I measured way back when. Anyway, my car came with the Muncie and I swapped to the T400 all the years I drag raced it and never had a problem just swapping yokes.

Thank you for the insight, sir. I like hearing from people with experience especially on a job this involved.

[nhcd538]

I'm starting to think maybe I should determine what year this 400 is and what it might have been out of before I order a flywheel. I will have to pull numbers off it in the spring when it comes out of storage. Or are all 60's and 70's 400's the same as far as flywheels go?

I'm sorry guys, it must be frustrating being a Pontiac expert reading through my confused drivel. I'm trying to learn.

[Hammertime Mike]

Originally Posted by nhcd538

Encouraging to hear that something like that is possible.

The person that made it work for me is pretty much in your back yard . Mike Felt is his name and he builds Pontiac motors. He lives in Hudson Falls. PM me if your interested in contacting him.

[JSchmitz]

Originally Posted by nhcd538

I assumed that was the case. A fraction of an inch difference shouldn't call for a new driveshaft in my experience.

Would this yoke work? If so, what does this "type" of yoke implicate as far as length of the driveshaft?

https://www.ebay.com/itm/162598893087

The driveshaft should be long enough to just clear the differential yoke when installed. You don't want the yoke hanging too far out of the transmission. It is only supported by a bushing. Don't want that thing hanging out there whipping around! I'll try to remember to post up pics of the two yokes I use. I think, from fully seated in the transmission, to engaged in the differential yoke, you only want 3/4". The one in the link is what I called the flat or square one.

[nhcd538]

Originally Posted by 'ol Pinion head

Yes, an original '67 GTO w T400 had a 59 3/8" long driveshaft with the med length 3R T400 yoke. For a '64-67 Pontiac A-body with a small output shaft Muncie, you'll need a driveshaft 60.00" long center to center on the 3R ujoints. .

I found a screaming deal on a rebuilt Dearborn Toploader 3-speed out of a 65 Mustang in the next town over. Would this be a feasible swap and what yoke and driveshaft length would I need? Would the Mustang version be compatible at all, or are the input shafts different?

I was planning Muncie 4-speed then this deal popped up - he's practically giving this toploader away and to be honest, the thought of the 3-speed doesn't bother me at all.

[Sirrotica]

This recollection is going back to the early 70s when I was in a partnership and racing dirt track 61 Pontiac bubble top cars. The front bearing retainer on the ford transmission is larger in diameter than the one intended for GM usage. This is where the throwout bearing slides, other than that item, they may be the same. Many years ago a swapped a ford bearing retainer onto a GM dearborn version transmission, because the retainer had cracked, and immediately found we would have to turn down the ford part to use with a GM style throwout bearing.

This was in the early 70s, so I can't remember if we even tried a ford throwout bearing on the Pontiac fork, or not. I do remember though using the ford retainer after turning the OD down to fit the gm bearing. You may have to use a ford clutch disc too, I can't remember if the spline on the input is the same, or not.

The Pontiac 3 speeds that came in the early cars were not all that beefy, plus they were almost impossible to find. That was the reason we were using a dearborn out of a GTO, in out 61 Catalina race car. We also had a 64 block so the GTO aluminum bellhousing, with the ford pattern was a natural to change into a stock car.

I'm fairly certain that some members on here have used the ford toploader 4 speeds in Pontiac cars, because they broke so many Muncies, maybe one of them will respond about the input spline and what clutch disc to use. Also the input shaft where the pilot bearing rides may require a custom made pilot bushing. It's been too long to remember all the details.

Hope some of my ancient recollection is a help to you.

[nhcd538]

Originally Posted by Sirrotica

This recollection is going back to the early 70s when I was in a partnership and racing dirt track 61 Pontiac bubble top cars. The front bearing retainer on the ford transmission is larger in diameter than the one intended for GM usage. This is where the throwout bearing slides, other than that item, they may be the same. Many years ago a swapped a ford bearing retainer onto a GM dearborn version transmission, because the retainer had cracked, and immediately found we would have to turn down the ford part to use with a GM style throwout bearing.

This was in the early 70s, so I can't remember if we even tried a ford throwout bearing on the Pontiac fork, or not. I do remember though using the ford retainer after turning the OD down to fit the gm bearing. You may have to use a ford clutch disc too, I can't remember if the spline on the input is the same, or not.

The Pontiac 3 speeds that came in the early cars were not all that beefy, plus they were almost impossible to find. That was the reason we were using a dearborn out of a GTO, in out 61 Catalina race car. We also had a 64 block so the GTO aluminum bellhousing, with the ford pattern was a natural to change into a stock car.

I'm fairly certain that some members on here have used the ford toploader 4 speeds in Pontiac cars, because they broke so many Muncies, maybe one of them will respond about the input spline and what clutch disc to use. Also the input shaft where the pilot bearing rides may require a custom made pilot bushing. It's been too long to remember all the details.

Hope some of my ancient recollection is a help to you.

A great help, thank you very much! If I used the Mustang transmission, I could probably just get a Ford throwout bearing (hoping it would work in the Pontiac fork - which I assume it probably would) and Ford clutch disc and pressure plate (10.5 or 11"). Like you said that leaves the pilot bushing/bearing which seems to be the biggest crap shoot. I don't own a lathe or know anyone who does custom stuff like that.

[Sirrotica]

Originally Posted by nhcd538

A great help, thank you very much! If I used the Mustang transmission, I could probably just get a Ford throwout bearing (hoping it would work in the Pontiac fork - which I assume it probably would) and Ford clutch disc and pressure plate (10.5 or 11"). Like you said that leaves the pilot bushing/bearing which seems to be the biggest crap shoot. I don't own a lathe or know anyone who does custom stuff like that.

On the pilot bearing, I believe that you could take a Pontiac bushing, and just drill the hole larger, because ford had a tendency to make more robust manual transmission parts than GM did in that time period. If anything I'd bet the ford input shaft is larger in the pilot bearing area. I do remember reading somewhere that the ford 4 speed toploader input shaft was 1 1/4 inches, which makes it much larger than the GM input shaft, but I can't remember what size the ford input shaft was on the ford 3 speed we robbed the bearing retainer off of.

I know we used a 10.5 inch disc, because Pontiac flywheels still hadn't been drilled for an 11 inch clutch, but the transmission we were using came out of a GTO, so it had the GM version input shaft already.

I'm sorry I can't recall all the specifics, but it's been over 50 years since I did all this. I believe the year I graduated from high school, making it 1970.....

[nhcd538]

I appreciate the insight sir.

[gtospieg]

IF the only issue is the pilot bearing, I'm sure that a local machine shop could drill it out to the proper spec. Hopefully that's the only issue and you actually have a local machine shop. Good luck. I swapped my 67 Tempest to a 4 speed back in '80 and at the time I was able to find all the Pontiac parts. At the time I hadn't ever seen any 4 speed Pontiacs. I just collected the parts and did the swap....I drove the car home from school on Friday as a 2 speed auto and drove to school Monday in a 4 speed Tempest....got pulled over on the first ride doing "I don't even know how fast you were going"(State Trooper quote, no ticket, strong warning)...ahh the good old days.

[nhcd538]

From what I'm gathering, finding the parts to swap in the Dearborn will be more trouble than its worth. Guess I'll stay with the original Muncie plan.

[400 4spd.]

In the mid 70's I used a 3 speed Dearborn for a while in my '67, and it's not that big of a deal to swap in. It was out of another '67 GTO that it was born in. The pilot bearing was not a problem for me when putting it in place of my Muncie. You will need the clutch disc for the Ford input shaft and the proper yoke for the output shaft. Of course you also need the shifter and linkage that go with the transmission. The Pontiac bell housing has provisions for the Toploader to bolt on, and the front bearing cap will fit fine within the bell housing opening.
I saved the drive shaft with yoke, along with two Toploaders out of GTO's. They haven't been on the road in 40+ years.

[nhcd538]

Can anyone recommend a good quality, oil impregnated bronze pilot bushing? And does anyone know what the correct size bushing is for a 60's-70'e era Pontiac 400?

Is this right?

https://www.jegs.com/i/McLeod/673/8-1380-1/10002/-1

I've also heard people recommend a bushing from Novak but the size isn't listed...

https://www.novak-adapt.com/catalog/...shings/gm1-gm/

Thanks again to everyone for the help. Picked up a nice bellhousing locally for $100, picked up a nice OEM Hurst shifter setup for a Muncie with shift rods for $250 (from someone who didn't know the value of what they had). I just ordered new shifter bushings for it as well. Progress!

[gtospieg]

The part number is 690023.. That is a Dorman part #. Advance Auto

[6d7gto]

Originally Posted by nhcd538

Can anyone recommend a good quality, oil impregnated bronze pilot bushing? And does anyone know what the correct size bushing is for a 60's-70'e era Pontiac 400?

Is this right?

https://www.jegs.com/i/McLeod/673/8-1380-1/10002/-1

I've also heard people recommend a bushing from Novak but the size isn't listed...

https://www.novak-adapt.com/catalog/...shings/gm1-gm/

Thanks again to everyone for the help. Picked up a nice bellhousing locally for $100, picked up a nice OEM Hurst shifter setup for a Muncie with shift rods for $250 (from someone who didn't know the value of what they had). I just ordered new shifter bushings for it as well. Progress!

Apparently, not all bronze pilot bushings are the same. Went through this a while back. I was told that they should be solid bronze (or they can mess up the input shaft). Anyway, someone recommended using a magnet to make sure there is no metal in the bushing.

I tested a couple and the ones from Ram Clutch passed but the Pioneer PB75 failed. I eventually went with an NOS 'bearing' which is what Pontiac used originally verses Chevy using bushings.