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74 Muncie Trans codes

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
I have an unrestored 74 454 4-speed. Where exactly is the P number that tells you what ratio muncie you have along with the date it was built? Is it on the passenger side main housing where the US Patent markings are? I could not find it there. Is it rearward and downward from there and still on the main housing? Is the print much smaller than the US Patent print?
 

duke94

Well-known member
Joined
Jan 30, 2007
Messages
277
Location
Ann Arbor, MI
Corvette
71' convert and 78' both Red
Code is located vertically on the right side of the case just ahead of the extension housing. The last letter will be the first gear ratio. A=2.52:1 and B=2.20:1. If you find the code, post it hear and I can tell you the MFG date.
 

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
74 454 and M21 muncie production numbers

For the 74, the production numbers are confusing to me. In particular, 454 option 3,494 built and the manual M21 option also 3,494 built! This doesn't make sense to me. I know I've seen many 74 454 with the turbo 400 automatics. Where are these taken in account? Did the two numbers really just happen to come out the same?
 

Wayne robson

Well-known member
Joined
Feb 24, 2007
Messages
169
Location
australia
Corvette
sold my last corvette.
the build

hi 74 454, the total build for 74 was 37502, 350 was 34008 , 454 was 3494 , total autos 25146, total m21 4 speed close ratio 3494, total m20 4 speed wide ratio 8862, so if you have a 454 close ratio and its numbers match, fairly rare . regards wayne.
 

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
Thanks everyone for your help. I finally found the P number towards the rear. Had to do some heavy duty cleaning. But I do have an M21 close ratio B. And the VIN number matches up. So it's original, and a low production run.

Thanks again.
 

74 454

Active member
Joined
Apr 25, 2007
Messages
31
Location
Michigan
Corvette
1974 Brown Coupe 454 4-speed
Thanks everyone for your help. I finally found the P number towards the rear. Had to do some heavy duty cleaning. But I do have an M21 close ratio B. And the VIN number matches up. So it's original, and a low production run.
 

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