This is clean
How rare is this corvette?
Drifting
Joined: Sep 2006
Posts: 1,259
Likes: 2
From: MS
Yes, should have UH for M20 or UK for M21 painted on the driver's side if it's still readable
Can also check the rear axle codes by looking at the underneath lower flange of the chunk.
Will probably be OJ for the 3.70 gears but could be OM for the rare 3.36s (only 428 built).
The M21 will have the 3.70 but the M20 could have either.
69any1, the L options are the engines: L48, L82, L88 etc.
The M options are the transmissions: M20, M21, M38, etc
Most of GM's options follow a certain pattern like this with similar option groups
all beginning with the same letter.
Can also check the rear axle codes by looking at the underneath lower flange of the chunk.
Will probably be OJ for the 3.70 gears but could be OM for the rare 3.36s (only 428 built).
The M21 will have the 3.70 but the M20 could have either.
69any1, the L options are the engines: L48, L82, L88 etc.
The M options are the transmissions: M20, M21, M38, etc
Most of GM's options follow a certain pattern like this with similar option groups
all beginning with the same letter.
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Team Owner
Joined: Aug 1999
Posts: 30,995
Likes: 99
From: Ontario
Rich,
I don't know the GM RPO codes very well but the shift from Muncie to Borg-Warner during the C3 run may have generated MM4 instead of M-20 or M-21.
http://img.photobucket.com/albums/v1...mission010.jpg
I don't know the GM RPO codes very well but the shift from Muncie to Borg-Warner during the C3 run may have generated MM4 instead of M-20 or M-21.
http://img.photobucket.com/albums/v1...mission010.jpg
Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
tranny that came together with the L-82 and rear is 3.70.1...
Thanks for the article...
Rich
Le Mans Master
Joined: Jun 2002
Posts: 8,339
Likes: 24
From: I can walk to MA
This chart makes it easy. Looks like the last number "1" is for production line.
http://fiedlerh.home.att.net/BW.htm
http://fiedlerh.home.att.net/BW.htm
Good find, there. YUP - looks like the Prince book has another error
in that last digit defined.
Drifting
Joined: Sep 2006
Posts: 1,259
Likes: 2
From: MS
Think the MM4 may have replaced the ZW4 used earlier and just means "standard transmission".
There were 2 different M20 trannies and which one you got depended on engine.
L48 - Saginaw 2.85 low
L82 - Warner 2.64 low
Rich, think if your car had the M21 you would see M21 on the build sheet and not MM4.
There were 2 different M20 trannies and which one you got depended on engine.
L48 - Saginaw 2.85 low
L82 - Warner 2.64 low
Rich, think if your car had the M21 you would see M21 on the build sheet and not MM4.
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Race Director
Joined: Feb 2005
Posts: 16,100
Likes: 17
Think the MM4 may have replaced the ZW4 used earlier and just means "standard transmission".
There were 2 different M20 trannies and which one you got depended on engine.
L48 - Saginaw 2.85 low
L82 - Warner 2.64 low
Rich, think if your car had the M21 you would see M21 on the build sheet and not MM4.
There were 2 different M20 trannies and which one you got depended on engine.
L48 - Saginaw 2.85 low
L82 - Warner 2.64 low
Rich, think if your car had the M21 you would see M21 on the build sheet and not MM4.
Rich