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#21
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Bob McNall was one of the engineers on that racing project. Tom V.
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"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#22
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this thread just makes me want to build an oddball car with cheap factory parts and see how fast i can go. something like an esprit, base firebird, or ventura with a 350 stroker, factory intake, and the 3 speed manual.
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#23
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Were the HD muncie 3spds similar ratio? I had a 68 Chevelle SS396 with the factory hd 3spd. Even had the console with the shift pattern. If you could beat someone by 2nd you were good, but there was too big of a gap between 2nd and 3d. Basically seemed like a 4spd missing 3d gear. It also had the habit of getting locked in first and 2nd at the same time if you shifted too fast.
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#24
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It has been mentioned a couple times here (including that prior post be "chevymad");
Unfortunately for this discussion, simply calling a "Muncie", doesn't benefit the matter; Granted when people say "Muncie" 99.8% of the time the 1963-1974 Muncie four speed is being implied. What seems to often be forgotten these days is that the "Muncie" name is an implication of the manufacturing facility, moreover the city that they were manufactured in. The Muncie plant made many transmissions, and the M-20/M21/M-22 are what most people think of these days. There were at least two in-house GM three speeds manufactured at the Muncie plant. The first in house Muncie three speed was manufactured from 1955 through 1965 - I understand these were the base "M12" RPO transmission in 1964, and replaced with the Dearborne unit in 1965. I do not know much about these three speeds. The second was a Muncie three speed manufactured for 1969 through to either 1975 or 1976 - the last year or two it was exclusive to trucks. This transmission came in two gear sets: A = 3.03 / 1.75 / 1.00 / 3.02R B = 2.42 / 1.58 / 1.00 / 2.41R I found the GM name for the Muncie three speed was SM-330, for reasons of clarity, I will use SM330 from this point forward. The SM330 was used mostly under RPO's MC1 & M13 - but the RPO doesn't mean it will be a Muncie three speed. The SM330 was intended as an in house replacement for having to source the Dearborne three speed, and by all accounts it is indestructible. I have never come across any first hand accounts of people having any issues with the SM330, it seems most were simply swapped for a four speed - not because anything was wrong with it, but a four speed had cool factor in spades over any three speed. As far as I'm aware, the SM330 had Chevrolet division exclusivity for the 1969 model year, and was used as the base transmission in all 1969 Chevrolet SS396 vehicles. For 1970, Chevrolet appears to have required a four speed for any Super Sport, but for 1970 & 1971 non-SS Chevelles with big blocks did received them as base equipment. It is my understanding that Buick and Pontiac used the SM330 first in 1970, I am pretty sure I know what years Pontiac used it, but I do not know what other years Buick used it. I am unaware of Oldsmobile ever using it. For Pontiac, starting in 1970, the SM330 was either the base, or base-required option for anything more than a 350-2bbl depending on the model in question. It was the base transmission for 1970 through 1973 GTO's. For the Lemans line, the SM330 continued to be available through to 1974. It was the base transmission for 1970 Formula 400's, and 1971 Firebird Formulas with either the 400 or 455HO engine. It was optional on 1970 & 1971 Firebirds as the "heavy duty 3 speed" option for 350-2bbl cars. After 1971, the SM 330 was no longer offered on Firebirds, and while the 350-2bbl cars still had a Saginaw three speed as base equipment, anything with a 400 or bigger, required a four speed or TH400. The real trouble with SM330 is that they are nearly identical to the Saginaw three speeds, the quickest, and most sure way to identify a Saginaw from a Muncie is the side cover; The Saginaw three speed has a single centred "ear" bolt boss: The Muncie three speed has two "ears" on either side of the top of the cover: In nearly every other way, the Muncie three speed looks like a Saginaw - except the castings are all unique, and other than maybe the output seal, nothing can be interchanged. To answer the original question (title): It depends on which three speed you're speaking about;
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) Last edited by unruhjonny; 01-18-2021 at 12:39 PM. |
The Following 2 Users Say Thank You to unruhjonny For This Useful Post: | ||
#25
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Thank You UnruhJohnny, for that info.
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The Following User Says Thank You to F ROCK For This Useful Post: | ||
#26
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That is interesting information on the early Muncie 3-speeds. It seems in my very early years working on vehicles, I may have had an early Muncie 3-speed apart. As I recall, it didn't have a synchronized 1st gear. It had a spiral drum on the main shaft that first gear tracked-on to engage the gear, only when the vehicle was stationary. Similar to reverse gear in some manuals.
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#27
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It has taken me a good while to garner the information that I have, and along the way, more than once, I nearly bought parts for the earlier Muncie three speed.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#28
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SM-330
I have several of each gear ratio transmissions. My '72 GTO came with the 2.5 first gear; much 'beating on' never bothered it.
The 3.0 (truck) transmissions have wider gears, and they are more straight cut. I never had a chance to try it out, but it should very stout. There are also some differences in tail housings, depending if it was for Chev or Pontiac (speedo location) and whether it was floor shift or column shift |
#29
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I have a truck transmission with the car (floor shift) tail housing and car (smaller OD) input bearing cover; I had hoped to change it over fully to the "B" gear set, but the second gear, and main/input elude me.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#30
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SM-330
Not sure this answers your question, but you do have to change all the internals when changing from one ratio to the other. I also recall something about the front bearing cover; I unknowingly used bolts that were too short and pulled them out of the case on launch!
Went to a 400; wish I had stayed with the 3 speed. If this is not useful, please explain further and I'll try to help. |
#31
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Interesting stuff for sure. The three speed gear boxes were always hard to sell... Mostly dirt track racers wanted them. |
#32
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No missed gears, shifter jambs, and worn out clutches, repeatable consistency, It's not the form of racing that appeals to me anyway (drag racing), I like corners incorporated into my racing, but have equally successful with T400 in dirt track cars, as well as autocross, and road racing. 99.9% of dirt cars, as Paul K lamented, have 1,2,3, or 4 speed manual shifted transmissions, but I never felt I gave anything away using a T400. For awhile, gutted Power Glides without convertors were in a good many late model stock cars. The early dirt cars I built back in the early 70s, (61 Catalina, Ventura's, bubbletop cars) we used the Dearborn 3 speeds, and ran them in 2nd gear to get the correct final drive. Never even a hint of problems with the Dearborns, but they also aren't shifting gears during the race. Since I drove semi for 7 years, I have zero hankering to shift gears on a street car. I have one IH wrecker with a stick in it, and if I had an Allison sitting around, the wrecker would also have an automatic in it too. Typically the automatic transmission is easier on drivelines too. The next street car I build will have a 4L80E in it. My late model 2005 GTO has a 4L60E in it. I bought it new, so I could have had a 6 speed in it, but was driving truck at the time, so the last thing I wanted to do in my D/D was to row gears. When I first got into street cars, and racing, everything I had was a manual transmission in it. After lying under them fixing all the driveline failures from clutches to rear axles, and everything in between, I bought my first T400 equipped GTO, and my time underneath the cars was reduced dramatically, as well as monetary expenditures for broken driveline parts, lesson learned. |
#33
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#34
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I am running a 3 sp. Dearborn in my 1967 Resto-Mod Convertible LeMans . I really like it. It does not shift fast from 1st to 2nd only because you're crossing the neutral zone, It is very positive and with the taller gears in the transmission along with the 3:23 the car was born with as was the transmission it is a great combo for me. In town driving from light to light in a lot of cases I don't even have to shift to 2nd gear. I am putting down 295 HP at the rear wheels with my little 389 with massaged #16 heads and a 2802 Summit cam. I am also running 235/60-14 Rally II's all the way around. Drove the car on a 1200 mile round trip it's first year of completion from a nut and bolt, frame off, rotisserie restoration to a Tribute GTO. Not even a hiccup on that trip or since and that was 2014!
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#35
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64 Lemans I had came with the three speed Dearborn. No synchro between first and second, so I had to come to a complete stop whenever downshifting back into first. It was a pretty tough unit, however when I swapped it out for a four speed muncie the driving enjoyment factor went up considerably. No more crunching on the downshift, plus off the line the lower first gear ratio made it jump considerably faster than on the three speed. If my Muncie blew up, I would not go back to the Dearborn unless there was not an available Municie left on the planet.
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Save yo Confederate money, boys, the South is gonna do it again! Pecosbill |
#36
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Non synchronized gears being the norm seems like a foreign thing to me, only because I can't wrap my head around why non-synchronized transmissions were even a thing past the 1950's...
I wonder if that 1964 with a Dearborn was swapped in some time early in it's life. As to Chevy mad, I don't know what to say. My information all suggests the first year it was used was 1969, and that being dubbed a Chevrolet part, Chevrolet got a full year of divisional exclusivity in using it for the 1969 model year. I wonder if your transmission was changed early in it's life? I would think that swapping a three speed from a 1969 Chevelle into a 1968 Chevelle would have been a cinch. If you can find any information that I haven't come across i am all ears - if anything, any new to me information might make finding parts easier.
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1970 Formula 400 Carousel Red paint on Black standard interior A no-engine, no-transmission, no-wheel option car. Quite likely one of few '70 Muncie three speed Formula 400's left. 1991 Grand Am: 14.4 @ 93.7mph (DA corrected) (retired DD, stock appearing) 2009 Cobalt SS: 13.9 @ 103mph (current DD; makes something north of 300hp & 350ft/lbs) |
#37
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If everyone is worried about to much power
for a 4 speed or 3 speed why not put a truck four speed or just be done with it and put in a Tremec
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JIM |
#38
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Dearborn heavy Duty 3-speed
One thing about the 3-speed transmission: Unless you have very deep gears you most likely will never see a '4th gear' before the finish line at the dragstrip. So the 3-speed was a very good choice for me as my cars never had deep (un-streetable) gear ratios out back. Yes they are heavy, but you probably aren't going to break it working it hard.
I have the answer to shifting it quickly: what I would call a 'pretty rare' NOS Hurst Inline Ram Rod shifter for this transmission. And it is for sale too !! Here you see it installed on a Saginaw 3-speed, and I'm quite sure it will work on a Muncie as well. I'm not finding any photos real quick of it installed on the Toploader, but I assure you it works there also since I still have my heavy Duty 3-Speed Dearborn that I would like to sell also. djtech65@hotmail.com |
#39
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My Pal in college, Robert Schneeberger (RIP Bob) had a Hurst Inline Ram Rod shifter for a 4 speed in his 1964 GTO Hard Top.
It worked very well in his Drag Car. It shifted a Muncie 4 speed. I was not aware that they even made a 3 speed version. Thanks for the new info on that Hurst Shifter. Tom V.
__________________
"Engineers do stuff for reasons" Tom Vaught Despite small distractions, there are those who will go Forward, Learning, Sharing Knowledge, Doing what they can to help others move forward. |
#40
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Jeff |
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