Quest for certain production number

Enzo_Guy

Veteran Member
Feb 18, 2008
106
Maryland
I am going tomorrow to look at purchasing a 1980 Camaro Z28 350 4-speed, and as far as I know it is all factory original (engine is a little hopped up). So how many 350 4-speed Z28s were made in 1980?
 

Gary S

Administrator
Lifetime Gold Member
Apr 14, 1999
24,665
Bismarck, North Dakota
That number probably doesn't exist. In 1980, Chevy coded all Camaro 4 speed trannys as RPO-MM4. That included Z28s, but they don't break the numbers down any farther than that.
In 1979, The Borg Warner used in the Z28 was a closer ratio tranny so Chevy coded it RPO-M21 and separate numbers exist so it can be identified from the wider ratio Saginaw trannys offered in other Camaros.
For 1980, the Z28 still got a Borg Warner, but it was the wider ratio version to handle the higher geared rear ends used in 1980 to help fuel mileage. Because Chevy chose to call both the Z28s Borg Warner and the other Camaros Saginaws wide ratio trannys, they decided to lump them together under RPO-MM4 instead of separating them out on the list.
 

RICARDO1969

Veteran Member
Lifetime Gold Member
Oct 14, 2007
2,086
Waukesha WI
Gary S said:
That number probably doesn't exist. In 1980, Chevy coded all Camaro 4 speed trannys as RPO-MM4. That included Z28s, but they don't break the numbers down any farther than that.
In 1979, The Borg Warner used in the Z28 was a closer ratio tranny so Chevy coded it RPO-M21 and separate numbers exist so it can be identified from the wider ratio Saginaw trannys offered in other Camaros.
For 1980, the Z28 still got a Borg Warner, but it was the wider ratio version to handle the higher geared rear ends used in 1980 to help fuel mileage. Because Chevy chose to call both the Z28s Borg Warner and the other Camaros Saginaws wide ratio trannys, they decided to lump them together under RPO-MM4 instead of separating them out on the list.
i have an 80 Z/28 and my build sheet has the 4 speed rpo-m21 left overs from 79 then?
CopyofIMG_1043.jpg
 

Gary S

Administrator
Lifetime Gold Member
Apr 14, 1999
24,665
Bismarck, North Dakota
RICARDO1969 said:
i have an 80 Z/28 and my build sheet has the 4 speed rpo-m21 left overs from 79 then?

No. The build sheet shows M21 so the assembly line knew that this car got the Borg Warner tranny, but if you have a copy of the dealer order sheet, it should list RPO-MM4 4 speed transmission.
The build sheet shows specific items that were not separately orderable as an RPO on the order sheet. About the only things listed on your build sheet that are separately orderable RPOs are the Z28 package, the radio, and the gauges. If you look at the rest of the sheet, pretty much everything else is part of the Z28 package.
On a non-Z28, most of those items would not be available. Some like F41, D80, and J50 are available separately on non-Z28 cars, so they show up on the RPO lists.
 

Hugger

Member
Nov 17, 1999
82
Oklahoma City, OK USA
The window sticker on my Z28 has RPO MM4 listed. BTW the Camaro White Book lists 12,237 cars built with the optional 4 speed transmission. Total camaro production was 152,005 with 45,137 Z28s built. Looking at those numbers, one could assume that approx. 10% of 1980 Z28s were built with a 4 speed.
 




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