[C2] 1966 Differential Code
Thread Starter
Racer
Joined: Jul 2018
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1966 Differential Code
My 66 427 390 hp differential code is AWW or possibly ANW 046EZ. I am trying to figure out what this is. I thought it was original but it looks like that is not the case. If it is AN code that would be from a 327, but the other letters don't seem to match anything from a 66. The second letter is very hard to read., it looks like N on an angle, or perhaps a W badly stamped so the first stroke of the W is missing. Could be a Z on its side for all I know. Another question is there any difference between a 327 and a 427 differential housing? Any help would be appreciated.
Tech Contributor
Joined: Aug 1999
Posts: 15,198
Likes: 4,026
From: Connecticut, USA
Off the top of my head BB diff codes started with F. I don't have access to my book right now to check it.
There is no difference between the housing or internal parts. The later BB used "HD" axles and 1330 pinion yokes.
The posi's were said to be shot-peened but they had lousy castings so they cracked anyway. If yours is out, you should check the posi case for cracks.
There is no difference between the housing or internal parts. The later BB used "HD" axles and 1330 pinion yokes.
The posi's were said to be shot-peened but they had lousy castings so they cracked anyway. If yours is out, you should check the posi case for cracks.
Thread Starter
Racer
Joined: Jul 2018
Posts: 429
Likes: 85
Off the top of my head BB diff codes started with F. I don't have access to my book right now to check it.
There is no difference between the housing or internal parts. The later BB used "HD" axles and 1330 pinion yokes.
The posi's were said to be shot-peened but they had lousy castings so they cracked anyway. If yours is out, you should check the posi case for cracks.
There is no difference between the housing or internal parts. The later BB used "HD" axles and 1330 pinion yokes.
The posi's were said to be shot-peened but they had lousy castings so they cracked anyway. If yours is out, you should check the posi case for cracks.
Drifting
Joined: Feb 2010
Posts: 1,734
Likes: 267
From: Richmond Texas
CodeRatioTypeAK3.36:1Standard Manual Transmission or Powerglide (327)
AL 3.08:1Positraction 4-Speed (327)
AM 3.36:1Positraction Manual Transmission (327)
AN 3.55:1Positraction 4-Speed (327)
AO 3.70:1Positraction 4-Speed (327)
AP 4.11:1Positraction 4-Speed (327)
AQ 4.56:1Positraction 4-Speed (327)
*AR 3.08:1Standard Wide-Ratio 4-Speed (327)
*AS 3.70:1Standard Close-Ratio 4-Speed (327)
AT 3.08:1Positraction 4-Speed (396/427)
AU 3.36:1Positraction 4-Speed (396/427)
AZ 3.55:1Positraction 4-Speed (396/427)
FA 3.70:1Positraction 4-Speed (396/427)
FB 4.11:1Positraction 4-Speed (396/427)
FC 4.56:1Positraction 4-Speed (396/427)
Note: All 1965-67 Corvette rear axles were manufactured at Warren and are suffixed “W”. Listed 1967 “AQ” and “AR” codes & ratios may only have been used early in the 1967 model-year, or not at all.
From WiIlcox Corvette page.
http://repairs.willcoxcorvette.com/1...es-and-ratios/
AL 3.08:1Positraction 4-Speed (327)
AM 3.36:1Positraction Manual Transmission (327)
AN 3.55:1Positraction 4-Speed (327)
AO 3.70:1Positraction 4-Speed (327)
AP 4.11:1Positraction 4-Speed (327)
AQ 4.56:1Positraction 4-Speed (327)
*AR 3.08:1Standard Wide-Ratio 4-Speed (327)
*AS 3.70:1Standard Close-Ratio 4-Speed (327)
AT 3.08:1Positraction 4-Speed (396/427)
AU 3.36:1Positraction 4-Speed (396/427)
AZ 3.55:1Positraction 4-Speed (396/427)
FA 3.70:1Positraction 4-Speed (396/427)
FB 4.11:1Positraction 4-Speed (396/427)
FC 4.56:1Positraction 4-Speed (396/427)
Note: All 1965-67 Corvette rear axles were manufactured at Warren and are suffixed “W”. Listed 1967 “AQ” and “AR” codes & ratios may only have been used early in the 1967 model-year, or not at all.
From WiIlcox Corvette page.
http://repairs.willcoxcorvette.com/1...es-and-ratios/
Last edited by SledgeHammer 2.0; Sep 24, 2018 at 06:11 PM.
Race Director
Joined: Oct 2000
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From: Shamong, NJ
"AW" was used to identify a 3:08 rear in 71, 73, 74 and 75. An extra "W" was sometimes stamped on rears, to identify the Warner Gear Division.
The the "046EZ" makes no sense to me. Rears usually had a date stamped on them, but they were always made up of one or two numbers for the month, one or two numbers for the day, and two numbers for the year. Letters were not used in the differential date stamp.
If you could post a picture of the stamping, maybe someone here could identify what the stamping is.
The the "046EZ" makes no sense to me. Rears usually had a date stamped on them, but they were always made up of one or two numbers for the month, one or two numbers for the day, and two numbers for the year. Letters were not used in the differential date stamp.
If you could post a picture of the stamping, maybe someone here could identify what the stamping is.
Team Owner
Joined: Oct 2000
Posts: 38,897
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From: Washington Michigan
Thread Starter
Racer
Joined: Jul 2018
Posts: 429
Likes: 85
new number
It looks like the last two numbers are E2 not EZ like I put before. It is the year I am most interested in, or what the E means. The whole code looks a little weird to me. Thanks
