What Muncie Transmission to use with a 454?
09-07-2012, 09:29 PM
#1
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What Muncie Transmission to use with a 454?
Specifically, what spline amounts do I need, and what else specific should I know? This is going in a 1973 that is receiving a 454, and is originally a 4 speed car.
Thanks
Thanks
09-07-2012, 10:35 PM
#2
Racer
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I THINK THAT CAR WAS AVAILABLE WITH THREE DIFFERENT MUNCIES...M-20 CLOSE RATIO - M-21 AND M-22 - OBVIOUSLY - THE M-20 WAS THE MOST WIDELY USED AND IS PROBABLY WHAT YOUR CAR HAD...(IF MEMORY SERVES ME RIGHT)
HERE IS A PIC OF THE NUMBERS THAT WERE IN MY 74 LS4 CONVERTIBLE
RR
HERE IS A PIC OF THE NUMBERS THAT WERE IN MY 74 LS4 CONVERTIBLE
RR
09-07-2012, 10:56 PM
#3
Melting Slicks
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St. Jude Donor '06
I have a rebuilt Muncie M21 out of my 73 parts car that was behind a 383 stroker for about 20 miles before I disassembled the car and parted it out.
If you are interested, I have everything except the pedal assembly, which went with the body and chassis.
PM me. I would like $1,000 for everything including a NOS vintage Hurst shifter that is super tight. The paperwork is from 1969.
If you are interested, I have everything except the pedal assembly, which went with the body and chassis.
PM me. I would like $1,000 for everything including a NOS vintage Hurst shifter that is super tight. The paperwork is from 1969.
09-08-2012, 11:06 PM
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You want a 26 spline input shaft vs a 10 spline. The 26 spline shaft is approx 40% stronger than the 10 spline, due to the fact that the 10 splines must be cut deeper to encircle the shaft with only 10 cuts - same idea as with axles.
Later boxes also have a 1 inch countershaft pin as opposed to the earlier 7/8" pin.
Beware that many "rebuilt" Muncies are junk because the cases are worn out around the countershaft pin. The pin is a press fit into the aluminum case, and although it cannot rotate 360 deg due to a flat notch machined into the aft end of it, some "wallowing" movement occurs over time. This causes an oil leak around the pin at the mounting flange of the trans. This is a chronic problem with old Muncies.Some people have machined the cases for a bushing with varying degrees of success.
Autogear Co has developed a "super case" that solves this problem with a thicker flange, and a soft plug in front of the countershaft pin. They also use a sealed front bearing. magnetic drain plug, and a stronger iron midplate is available. Check them out at autogear.net. They sell cases/parts, as well as complete new Muncies.
Later boxes also have a 1 inch countershaft pin as opposed to the earlier 7/8" pin.
Beware that many "rebuilt" Muncies are junk because the cases are worn out around the countershaft pin. The pin is a press fit into the aluminum case, and although it cannot rotate 360 deg due to a flat notch machined into the aft end of it, some "wallowing" movement occurs over time. This causes an oil leak around the pin at the mounting flange of the trans. This is a chronic problem with old Muncies.Some people have machined the cases for a bushing with varying degrees of success.
Autogear Co has developed a "super case" that solves this problem with a thicker flange, and a soft plug in front of the countershaft pin. They also use a sealed front bearing. magnetic drain plug, and a stronger iron midplate is available. Check them out at autogear.net. They sell cases/parts, as well as complete new Muncies.