64 Diff. Code?
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
The Julian date code (3 3 4) pretty much confirms that it's a '78 or '79 3.55 Posi ("OH") axle, made on the 334th day of the year. The casting date will be on the driver's side, partially hidden by the front of the strut rod bracket. 
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan
Yup - the 464910 rear cover was used in '78-'79, with the 7/16" rear spring retainer plate bolts (vs. the 1/2" bolts used from '63-'77) to accommodate the '78-up 2-1/4"-wide spring.
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Intermediate
Joined: Nov 2011
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From: Monahans Texas
JohnZ,
As you stated in an earlier post, there is a P-code on the side of the muncie 4-speed in my car.
It is: P8T18
If I understand it correctly that means it was built on December 18th,
1967 , for a 1968 car.
Still not sure if it is a M20, M21 or M22.
As you stated in an earlier post, there is a P-code on the side of the muncie 4-speed in my car.
It is: P8T18
If I understand it correctly that means it was built on December 18th,
1967 , for a 1968 car.
Still not sure if it is a M20, M21 or M22.
Team Owner
Joined: Oct 2000
Posts: 38,897
Likes: 1,926
From: Washington Michigan