CRG Discussion Forum
Camaro Research Group Discussion => Decoding/Numbers => Topic started by: sftibbs on September 30, 2009, 09:21:42 PM
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My 4 speed Muncie is stamped with my VIN # so I know it matches my 69 Camaro. However the tranny code is P9S27A. Decoded, it tells me it was a M20 built on November, 27 1969. The problem is my car was built in January 1969. Can anyone help with the disparity? Thanks.
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My 4 speed Muncie is stamped with my VIN # so I know it matches my 69 Camaro. However the tranny code is P9S27A. Decoded, it tells me it was a M20 built on November, 27 1969. The problem is my car was built in January 1969. Can anyone help with the disparity? Thanks.
The 9 in your transmission assembly code refers to the model year, not the calendar year, so your transmission was assembled on November 27, 1968.
Paul
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That makes sense. Thanks for the clarification.
Steve
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Check out this link. http://www.camaros.org/drivetrain.shtml#trans
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Perfect. I was able to decode the Muncie. Thanks for the link.
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So, what your car? SS, Z, or LM1?
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It's an SS 350...very original and straight, which is good for my first restoration. Also has the fold down rear seat which was a rare option. I was hoping it was outfitted with the M21 but it came with the M20.
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The M21 was never available with a SS350, the M20 was the only 4 speed available.
http://www.camaros.org/diffs69.shtml
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Okay, thanks. What's the difference in the two as far as what they were built to do?
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The M20 and M21 refer to the internal gear ratios, more specificaly the ratio spread. The M20 is a wide ratio and the M21 is the narrow ratio. Both transmissions have the same 1:1 4th gear but the M21 has the ratios set up so the RPMs do not drop as much when you shift gears as compared to the wide ratio M20. If you have a torquey engine with power over a wide range the M20 is preferred. If you have a more high strung, high RPM powered car, the M21 was preferred. Speaking in general. :)
-Mark.
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For crusin' the wide is preferred due to the 2.52:1 1st gear. A Z/28 with a wide ratio and 3.73s has a total 1st gear of 9.40; with a close ratio it is 8.20. A friend built his '68 Z/28 with the one year only 2.56 1st Muncie.
The shift into 4th with a wide seems like a 40 mph headwind though...
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Good information...thanks.
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So, what your car? SS, Z, or LM1?
I may be wrong but I didn't think the LM1 could get a Muncie 4 speed.
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I may be wrong but I didn't think the LM1 could get a Muncie 4 speed.
Russ -
You're right about being wrong! ;D
You could get a Muncie 4-speed with the LM1; read this...
http://www.camaros.org/lm1.shtml#drivetrain
Paul