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Username Post: '64 'Vette Transmissions        (Topic#374771)
rrausch 
"19th Year" Silver Supporting Member
Posts: 15115
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
03-31-24 04:59 PM - Post#2868482    

Did the '64 Vette come with a BW T10 or Muncie 4-speed? Anyone know?

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 


Brickwhite 
Contributor
Posts: 362
Brickwhite
Loc: Colorado, Denver
Reg: 09-05-19
04-01-24 08:15 AM - Post#2868501    
    In response to rrausch

powerglide 2 speed auto and 4 speed muncie in the C2s 63-67..

Muncies can be picked up for 800-1000 in decent shape.



Gears are sometimes hard to get these days.

Ted


Edited by Brickwhite on 04-01-24 08:16 AM. Reason for edit: No reason given.

 
rrausch 
"19th Year" Silver Supporting Member
Posts: 15115
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
04-01-24 01:13 PM - Post#2868507    
    In response to Brickwhite

Thanks Ted. I had a BW T10 in the '58 Vette in my avatar. I was running a '67 crate 327 with double-hump heads and a Quadrajet. Hope to get another 'Vette before too much longer.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
rrausch 
"19th Year" Silver Supporting Member
Posts: 15115
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
04-01-24 01:17 PM - Post#2868508    
    In response to rrausch

I've never understood the advantages of the wide ratio vs narrow ratio Muncie. Can you explain it?

Back in the day my girlfriend had a '59 Vette with a 396 and a Muncie and I really didn't like shifting it--it was difficult to shift.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 
Brickwhite 
Contributor
Posts: 362
Brickwhite
Loc: Colorado, Denver
Reg: 09-05-19
04-01-24 01:42 PM - Post#2868510    
    In response to rrausch

Stolen from - DZAUTO on the Corvette forum.

In the beginning (63) when the Muncie replaced the Borg-Warner T-10, the 4sp transmission option was M20. Period. Depending on engine/rear gear ratio, the car was delivered with either a wide ratio or close ratio Muncie. The option was still M20 for the 4sp.
In 1966, the two ratios were broken down into seperate option codes: M20(wide ratio) and M21(close ratio). The Heavy Duty 4sp transmission was the M22-----------------AND IT WAS CLOSE RATIO ONLY! The M22 was first used in the 65 model year, but such a very small quantity (maybe 20-40 delivered) were delivered that they are ultra rare, and it appears they were only delivered in 396 cars.
The close ratio Muncies have ALWAYS had the 2.20:1 first gear ratio, but the 63-65 and 66-74 wide ratio ratio Muncies had slightly different first gear ratios. The 63-65 had a 2.56:1 first gear ratio and the 66-74 had a 2.52:1 first gear ratio.

Paul explains it better here:

https://www.5speeds.com/muncie2.htm

https://www.5speeds.com/ratios.html


Borg Warner's extra low ratio Super T10 had a 2.88 first, 1.75 second, 1.33 third and 1:00 fourth. Notice if you plug these gear ratios into the above formula you will end up with the following drops; 39%, 24%, and 25%.

Think of gear ratios as a distance between 2 points. In a typical muscle car 4 speed application fourth gear is direct or 1 to 1. Again thinking in terms of distance, consider fourth gear or direct as your final destination. The further you get away from 1:1 ( direct ) you in a sense get wider. The Muncie M21 and M22 Close ratio 4 Speed was the closest ratio 4 speed ever put into a production car. It's ratios were 2:20 first, 1.64 second, 1.28 third, 1:00 fourth. If you plug those ratios into the formula in figure 1 you will end up with 25%, 22%, and 22%. Compare these percentage drops to the previous drops found using the Super T10. Notice that although the 2-3 and 3-4 drops of the Super T10 and Muncie are pretty close percentage wise, the 1-2 drops vary quite a bit. The reason is that the Super T10's have a lower ( higher numerical ) first gear. The 2.88 and 2.64 ratios are further away from direct than the Muncie's 2.20 first gear ratio.

What makes close - close?
What you have learned is that you can't gain distance without loosing closeness. The lower the first gear, the wider the 4 speed will be. If one were to look historically on what a close ratio box was, it usually meant a gearbox that had 25% or lower drops across all gear spreads. The problem is that when the Muncie close ratio box was designed in the 1960's we really didn't worry much about gas mileage. In order for you to get a "close ratio" Muncie your car had to be equipped with at least a 3.70 rear end gear. You needed at least that low of a final drive to get your car moving. The "wide ratio" M20 had a 2.52 1st gear. You could get a 3.31 or 3.55 rear with that, gain a little more economy, but it wasn't cool to have what they considered a wide ratio box in your Corvette. By late 1974, fuel economy and air pollution were considerations. Catalytic converters were mandatory by 1975. Axle ratios had to drop to get the better gas mileage the EPA demanded. So in order to get cars moving with 3.08 or 2.88 rear end gears, cars that had engines with decent amounts of low end torque had "close ratio" transmissions with 2.64 first gears, and with smaller cubic inch engines first gear ratios in the 3.0 range. So the newer close ratio transmissions are wider than the older wide and close ratio transmissions!

What works and what doesn't?
Doug Nash Corporation had an interesting solution to this dilemma. Make a 5 speed box with a close ratio spread like a Muncie M21 and make 5th gear direct. Again think of what I said about distance between two points. The more stops you make in your travel to get to your final destination the closer the distance between your stops. By adding a lower first speed gear and keeping a direct 5th, you gained more distance, but added an extra stop. The Doug Nash Street 5 speed came with a 3.27 first gear. This allowed drag enthusiants to use a 3.08 final drive and still get good close ratio acceleration. This worked great.



Ted


Edited by Brickwhite on 04-01-24 01:49 PM. Reason for edit: No reason given.

 
rrausch 
"19th Year" Silver Supporting Member
Posts: 15115
rrausch
Loc: L.A, Cal. & St. Louis...
Reg: 04-07-03
04-02-24 08:01 PM - Post#2868543    
    In response to Brickwhite

Thank you Ted (and thanks DZ Auto--Tom Parsons). That really explains it well.

1953 210 Convertible, 261 with dual Carter YF 966S carbs, P.S., Remote Bendix P.B. Booster... shade-tree restoration about done.




 


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