Big Mikey

Hi guys I am newer to the forums but not to working on cars, just traded my old 53 Bel-Air for a 68 cutlass s with a rebuilt motor, rebuilt suspension, rebuilt 4 wheel drums, new clutch, etc.... Anyhow the car came with 3 on the tree and the previous owner went with a piece of crap floor shifter, I am thinking Hurst shifter but wanna swap to a 4 speed.

So here come the questions:

Will the bellhousing be the same?
Should the shifter to in the same hole in the floor?
Will the driveshaft be the same length and splines match up?
Will the trans mount from the Saginaw 3 speed be the same for a Saginaw 4?

Like I said some of the things like holes in the floor are not a bad fix, but if I need to find a different trans mount and driveshaft with have to be cut/changed or other things that might turn this job to a nitemare I may just leave the 3 gear and hurst shift it...

Any and all help/good advice is appreciated and thanks!! Oh yeah because I am on a tight budget a Muncie is out of my price range, but I usually can find a Saginaw fairly cheap, so that's the plan.

rktolds

Pretty sure this is a straight forward swap. My 68 F85 has a 3spd on the floor and will have a 4 speed one day. You will need a new shifter for the 4speed. Not sure on the driveshaft, but the bellhousing will work.

DeltaPace77

While more money still, you may want to consider a 5 speed od tranny. Friend of mine with a 79' Vette did this, and big difference cruising on the highway. My car originally had a 3 speed auto TH350 tranny, I replaced with a 4 speed auto od TH700R4 tranny, and wish I'd of done sooner, especially with the price of gas. Had to shorten the driveshaft a bit, and use an adapter to the Chevy bolt pattern, but minor set backs.

Rickman48

I'd save my pennies a little longer and wait to find a Muncie.
In my experience with saginaws, they last about a week - weak junk!!
Input and output shafts are different, meaning different clutch disc and yoke.
I believe even the linkage is different, too.

66-3X2 442

If you're on a budget and want a good trans for your car,you may want to consider the Mother of all 3 speed trans,the Ford toploader. Some late 65 442's and all 66-69 442's that came with a 3 speed trans came with it. Also if you ordered a 66-69 Cutlass with a floor mounted 3 speed trans,it also came with the toploader because they didn't have a floor mounted shifter for the 3 speed Saginaw. The toploader is the reason that all BOP bellhousings have 2 bolt patterns for the trans. The Muncie/Saginaw use the same pattern and the toploader the other pattern.The toploader is virtually bullet proof and are great transmissions. I have the complete set up for sale if you're interested in going with a 3 speed over a more costly Muncie. If you want to still use a Muncie,I don't blame you @ all. Pontiac also used the toploader,not sure about Buick and Chevy did not use it. Oldsmobile didn't call it a Ford trans because of the obvious,they called it a Dearborn,wonder where they got that name from? I had a 66 442 F-85 Club Coupe that had the toploader trans and was a column shift. They dropped the column shift option in the mid 66 model year run and didn't offer it again.

oldsmobiledave

If you are changing from the original 3 speed skip the 3 speed & 4 speed swaps & move up to a 5 speed OD (Richmond or Kessler) or go all the way to a 6 speed. Do it once & do it right.

66-3X2 442

Do you still have the 66 Black use to be Blue 3 speed car or do I have you confused with somebody else?

oldsmobiledave

I sold that car in 2009.

It made its way to a new owner in southern Alberta then got traded for a 57 Chevy Bel Air in Winnipeg. That owner sold it to another Olds enthusiast in Winnipeg who kept it for two years. He then traded the car in on a Cadilac SUV @ a GM dealer in Ontario in 2012.

That 66 post coupe is in the Canadian Autotrader online. It is at a dealership called Forbes which I think is in the GTA (Greater Toronto Area). They are asking $29,900 for the car.

That car was one of roughtly 247 330 cars with factory 3 speed manual trans. It had been converted to a 4 speed Muncie from a 1966 442 prior to me buying the car. I still have the 3 speed top plate to the console.

This is the car

Black66OldsCoupe006.jpg

Black66OldsCoupe008.jpg

Black66OldsCoupe025.jpg

Black66OldsCoupe024.jpg

66-3X2 442

OK,I thought you were the guy who had it. I almost bought the car when it was in FL and still had the 3 speed trans. It was light blue then and was very solid the best I remember. It's certainly been round the block a time or two hasn't it?

oldsmobiledave

You remeber it when it looked like this.

Big Mikey

Sorry but a high end 5 or 6 speed is way out of the budget, I have a wife and little girl that is very demanding on my budget!!! The 3 speed in the car works just fine with the exception of the shifter, I just thought that 4 gears would be a lot more fun than 3.

garys 68

I'm about 99% certain the Saginaws (even 3 speeds), Muncies, and T10s have the same bell housing pattern, so swapping for any of the above should work. The saginaws are by far the weakest and dont cost much less than other common 4 speeds. Consider a Muncie or T10. Get a later one with 1" countershaft, much less prone to leaks.
One issue to consider are the gear ratios in your 3 speed Saginaw. I think they came with 1st gear between about 3.5 to about 2.5:1.
The muncies are available in around 2.6, 2.4, and 2.2:1 first gears
T10s 3.42, 2.88, 2.6, 2.4:1 first gears
Depending on the rear end ratio you probably dont want to change your first gear to too much of a lower numeric value. You'll be very unhappy with the acceleration/drivability if you do.

joe_padavano

Let's back up. The Muncie four speed is a bolt-in replacement for the Saginaw three speed. Everything is the same (except, of course, the shifter). Note that there are two input shaft types, the ten spline and the 21 spline. If you want to use your existing clutch plate, get a Muncie with the same input shaft as your current trans.

Just be aware that musclecar restorers have driven the price of Muncies into the "stupid money" range, so the five speed isn't THAT different. On the other hand, while the Muncie is a bolt-in, all available five speeds will have a different length that requires relocating the trans crossmember, building a custom driveshaft, and possibly changing the e-brake cables. The larger Tremecs also require tunnel mods to fit.

Indy_68_S

Just an FYI..The factory 4 speed for a '68 Cutlass was the Muncie M-20 w/ a 2.52 first gear.
But, like garys 68 said, you'll need to consider your rearend. If your Sag3 has a 3.5 first and your rearend is something like a 2.56, the Muncie's 2.52 first would feel different.
They have for the most part...BUT, if you're not in a hurry, just keep sniffing around. I did for a year & finally scored a very nice M-20 w/shifter & rods for a fraction of what you see the bare trans for in classifieds. There are still people out there who see them as just another car part...

66-3X2 442

Off topic a little and I'm sure I'll get some feedback from my statement but I'm saying it anyway. They can throw every M-21 Muncie in the ocean and the world would be a better place.

Rickman48

66 - what's your reason?
Yes, I agree going from a 3-speed to a 4-speed is a real difference, especially a close ratio. A wide-ratio [M-20] isn't as bad, with a 2:54 1st.
1st car [56 chebby sb] went from a 3-speed to a M-22, even a 4:11 gear made it feel like it was starting in 2nd.

66-3X2 442

My experience is that the M-20 2.52 1st gear trans is a lot more peppier in the heavier cars like ours. If you have any kind of gear behind a M-21 trans,you can't tell the difference between 3rd & 4th gear,the engine doesn't even change sound. I understand the theory behind a close ratio trans but I'm not buying it. The gear spacing is more even with the close ratio but I feel that the lower first gear coupled with the deeper drops between gears in the wide ratio makes for a better trans. Most of our cars are between 3600#'s and 4000#'s and they need all the help they can to get moving. I ain't trying to pi$$ nobody off calling their M-21 trans junk,I just think and prefer the wide box,that's all.

garys 68

I'll go one step farther, I put a 3.42 first gear T10 in a 72 with a 2.73 rear. It's behind a 5.3 LSx with an amazing torque band for a 327. Great combo.
But before we get off topic...any Muncies or T10 from early 60s to around 82 from any GM car will bolt up. I chose the 3.42 1st gear T10 because of my combo, found one locally for $100. Add a complete rebuild kit with torque-loc sliders for another $150. You got a new trans.
You can also usually adapt a 10 to 26 spline input shaft by simply getting a new disc when the trans switched from 10 to 26 spline, around 1972.
You can also still buy new Super T10s from Richmond gear, and buy or build an upgraded (Supercase) Muncie with 2.20 to around a 3.0 1st gear from aftermarket manufacturers (Autogear).

oldsmobiledave

I agree 100%. The best Muncies are the 1971-1973 versions (as found in Olds). My 72 W-30 came stock with one & I have a spare from a car built 1 month before mine.

With the M-20 you can run a 3.23-3.31-3.42-3.55 gear set (depending on diff used) & never be in a bad gear. If the Muncies I think it is the most versatile. Ofcourse the M-22 is far stronger but for stock engines the M-20 is fine.

Big Mikey

So it seems that this swap will most likely open a new can of worms, I don't plan on swapping the rear gears. I just thought that I might actually gain something from this swap, the car is just my toy cruiser for me and family-so it seems that leaving the perfect working 3 speed alone and spending $$$$ elsewhere is the real answer.

copper128

If it's just a driver/cruiser, get yourself a nice Hurst shifter and be happy. Use the money you saved on the trans swap to pay for gas and burgers.

garry442

If it's just a driver,find a Saginaw 4 speed,and a shifter for a '68 Chevelle.Everything will fit.Enjoy the car.