Hot Rods Heavy duty Muncie 3 speed?

Need help in understanding what I have. Transmission came out of a 1972 Pontiac LeMans 455. I've been told it is a 3 spd Muncie, has synchronized 1 gear, 3.09 1rst, 1.75 2nd and 1.0 final.

I've been looking up info on this and haven't figured out the correct search words on the general web to use for finding tech info.

I have a Hurst synchro-loc dual pattern shifter. Looking for the correct plate to mount this shifter on the transmission. Is there anyone out there who can help me with a part number?

It will be going behind my fresh built 401 Nailhead in a Model A.

Pics of the transmission numbers and shifter attached.

Thanks.

 

Here's some info on your shifter... doesn't show any mounts...also included a picture from a early shop manual ... Hurst linkage but the picture is of just a generic 3 SPD trans....

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Why not just use the current mounting plate; you may have to re-drill it to fit the Synchro-Loc? There is a Hurst mount that bolts to the underside of the extension housing using the trans mounts bosses, and a large U-joint at the end of the extension housing. There's always one or two on that auction site we all know and love.
I am Butch/56sedandelivery.

 

Thanks for the nomeclature.

If I can't find the mounting plate, I can make this one work, I was hoping to find a Hurst piece specific to my setup.

Anyone know about the transmission? I had no idea there was an Iron case 3 speed Muncie for heavy duty applications. Seems like everyone was swapping out for the 4 speed and every search I had talks about the Dearborn 3 speed and the weaker Saginaw.

I went this route because it was recommended with the 401 power curve and low RPM. Seems like 4 speeds on Nailheads are kind of a waste due to the torque not needing second gear. Since this came behind a 455 Pontiac, I figured it could hold up to my Nailhead.

 

Had to dig a bit to figure out where this catalog was stashed but here's some install kits that might work. Your transmission code is 351 and only shifter option shown is a Mastershift which looks similar to the Syncro/Loc.

 

https://www.ebay.com/itm/367-7952-H...938497&hash=item58d1745d99:g:y8sAAOSwEgVWTf6-

 

Thanks Matt!

 

No prob.

 

So it's a 351.

 

That's just how Hurst identifies it in their chart, actually a Muncie SM-330? Think column shifted versions come with a smooth tail housing and require a different shifter kit too.

 

Would help if we could see the tail shaft housing...does it have any thread holes in it like the picture of the 351...if it has any of the three bolt pattern combinations and if your hole in the tunnel has to be in a certain place than I believe any of the mounting plates would work....this one in the picture is a four speed but I believe the three SPD. has the same bolt pattern size

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I just now saw this thread; almost a year later. How did your A come out ? I've been running a 401 in my '36 since 1965 so I wanted to comment on your 3 speed ratios: the lowest ratio I have ever used ( 2.39 x 4.1 ) in Low gear is 9.8-1 with 'normal' sized tire circumference; much lower than a 401 requires ( altho' it's a lot of fun ). To compare: your 3.09 ratio in Low gear with a 3.23 rear end would still be lower at 9.98 than my 9.8. - My point is that you can run a very high rear end ratio without compromising on acceleration thru the gears.

 

Yes, It's a Heavy Duty Muncie 330 transmission; came in trucks and big block/high HP small blocks. A lot of guys get "confused" thinking they're a Saginaw, but NO WAY; a LOT stronger; they also look like more of a "box" the extension housing is bolted to (sort of the give-a-way, that and the different from Saginaw, 7 bolt side cover). The Hurst catalog shows it as a 351 kit. Can't see your extension housing (hid behind the Mickie Mouse plate); if it has bosses,l then it came in a floor shift car, no bosses, it was in a column shift car or truck. Hurst should be able to supply something; if not, you have enough parts to make it work with the other shifter's hardware. I am Butch/56sedandelivery.

 

I want to thank everyone for the comments after I last posted. The transmission is in storage right now until the folks at the Haifley Bros. doing the fabrication work are finished buttoning up the body. I ordered that Hurst kit that Matt linked me to, which is another big help in figuring out linkage and mounting. I have a couple books on rebuilding Muncie 4 speeds, but trying to find more detailed info on this SM330 isn't easy, even with the internet. I found some rebuild parts on www.drivetrain.com, but the transmission is in good order and should hold up to the torque dished out via the Buick.

I rebuilt the 401 Nailhead with a minimal overbore to clean up the cylinders. It is relatively stock for a rebuild, using TA Performance Roller rockers and a TA-25 camshaft with a rebuilt/recurved distributor courtesy of Matt Martin at Centerville Auto, that Edelbrock intake (see the avatar) with dual 600 cfm's there abouts.

I am still looking at rear gears, thanks for your real world advice Sixhundred Sixteen, I am leaning between 2.75-3.25. This car will be making jaunts across the desert on hot rod runs with my friends and out of state shows. I've attached a couple pics if you want to see what is going on.

 

When I worked in the Esso Station in high school someone brought in his 396 Chevelle, I was shocked to find he had ordered it with a 3 speed rather than a 4 speed. Found out later that with the limited tires
available then he could run with the 4 speed cars, and that torque was the way to go on the street.

 

I have a friend who inherited his Uncle's 69 Camaro SS396 that was ordered new by the Uncle. It had the 3 speed, he later changed it to a 4 speed. My friend has the original transmission and all the paperwork from when car was new. I think he told me there was a upcharge of something like $20-$25 difference in the two transmissions, so his Uncle went the cheaper route.

 

This Muncie 330 3 speed, when ordered with a floor shifter, had the mounting bosses on the extension housing; if it was a column shifter, like in a truck, then there were't any bosses for a shifter on the extension housing. I wonder how many SS 396 Chevelles got ordered with the 396 and a column shifted 3 speed? I am Butch/56sedandelivery.

 

Pretty sure floor mounted shifter was designated if manual shift was ordered on any SS, Butch. I did own a column shifted SS automatic though.

 

I remember in about 1969, while working after school in the local Chevron Dealer Station, a customer had a 1969 Chevelle 300 2 door sedan with a 396 AND column shifted 3 speed. I don't know if he bought it that way, or if it had been ordered that way, I just thought it was a really odd combination. Worked with a nurse who's husband bought a 70 Monte Carlo with a 3 speed manual on the column; the guy who originally ordered it never picked it up, and the dealership had a hard time selling it. I am Butch/56sedandelivery.

 

In 1966; a Nova with the 327/350 hp (L79) engine came standard with a column shifted three speed, a Muncie four speed was an extra cost option whether it was a Super Sport hardtop or a four door sedan or station wagon (yes, they made a few).

 

Thanks for the tread looks like this three on the tree HD muncie 12 bolt differential with center support bearing will be a nice project God willing!

 

Update, I couldn't use this due to not being able to find a tail shaft that had a mount like 4 speeds had. Not sure how this was originally mounted in the car it came out of, however I sourced a Heavy Duty Borg Warner T-16 3 speed which was used behind 421 Pontiacs. It has a synchronized 1rst gear, Ratios are 2.86 1rst, 1.72 2nd and 1.00 final.


Here it is in the chassis.

 

Nice project ! Most of the 3 speed big block cars were bought that way because of the insurance up charge for muscle cars having a 4 speed. I worked at a Pontiac dealership in 66-67 while in high school.
Guys would come in and order the car with a 3 speed for the insurance break. Then drive over to the service dept. and swap the 3 speed for a 4 speed. There was a jump in insurance rates as soon as the insurance companies saw the 4 speed code on the car.
We must have had a dozen brand new 3 speeds laying in the back of the dealership. The sales dept worked out a deal for the customer on the swap and hid it in the finance papers under special dealer prep package. That way the customer could include it in the financing. GMAC went along with it.
The Chevy dealer did the same thing as well as the Olds dealer in my home town.

 

That is interesting !!

 

That is when I lived in Charlevoix . The Chevy dealer sold 3 new Corvettes in 67 with 3 speed manual transmissions. How rare would those cars be today? One of my high school teachers bought one and she kept it a 3 speed stick car.
One of my classmates dad owned the Olds dealer and bought his kid a ram air 400 442 2 door post car with a 3 speed floor shift. They changed it over the first week to a 4 speed , but the option code said 3 speed. The insurance for a 18 year old with a car like that was bad enough . Add on the extra premium for one more gear almost doubled his policy.

 

I just sold a completely stock, 1969 Camaro that came from the factory with a 350", 2 barrel, and a 3 speed
on the column and bucket seats. Everyone assumed it was an automatic because you had to put it into reverse to remove the key.

 

they made quite a few 3 speed Camaro's. Especially 6 cylinder cars.

 

I know of one 71 Pontiac GT-37 that was ordered with a 350 and the Muncie 330 HD. I just bought said 3-speed that sat in the garage for 18 years. Owner thought it was a Saginaw. I did too! It looks like new inside and out. His wife said, “Didn’t you have it rebuilt?” He said yes. Now to find a bell housing and figure out how the linkage is going to work on my column shifted Chevy II 6 cyl.

 

I remember people blowing up there 4 speeds in there new 64-66 GTOs and switching to the three speed. One guy in my alley had a 421 with a SD#10 cam in his 64 LeMans. He went through a pile of 4 speeds before getting a heavy duty three speed. He said his car was faster too..

 

Those GTO 3 spds were Ford trans missions, at least in '65, my sister had one.