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Recently, there has been some discussion regarding 63-74 Corvette half-shafts. I promised to provide some additional information and here it is:
First off, folks need to understand that there were 2 ways that half shafts were supplied. Half shafts used for PRODUCTION were supplied to St Louis as complete assemblies which included both u-joints and the outside u-joint flange. So, the PRODUCTION part numbers were those for the assembly and not the bare half shaft. The half shaft assemblies, as used in PRODUCTION, were never available in SERVICE. Although u-joint part numbers varied from 1963 through 1966, the part number for the PRODUCTION half-shaft assemblies was not affected.
For SERVICE, the individual parts which made up the PRODUCTION assemblies were available. The part numbers for the pieces which made up the PRODUCTION assemblies were the same as those available in SERVICE.
PRODUCTION assemblies:
1963-only-----GM #3840317. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3832048 flange, and 2 GM #3823102 u-joints. It was used for ALL 1963 Corvettes;
1964----------GM #3847899. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3840318 flange, and 2 GM #3851520 u-joints. It was used for ALL 1964 Corvettes;
1965-1974 small block----GM #3847899. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3843018 flange and 2 GM #3877040 (1965) or GM #3889696 (1966-74) u-joints;
1965-74 big block-----GM #3882785. This assembly consisted of 1 GM #3872908 half shaft, 1 GM #3843018 flange, and 2 GM GM #3877040 (1965) or #3889696 (1966-74) u-joints.
SERVICE half shafts:
1963-1965 small block-----GM #3832044
1965 to March, 1966 big block----GM #3872908
March, 1966 to 1974 ALL----GM #3872908
The GM #3832044 small block half shaft was discontinued from SERVICE in March, 1966 and replaced, for all 63+ SERVICE applications, by the big block half shaft, GM #3872908. When both were last available in 1966, both carried the same GM list price of $17.30. So, that would imply that whatever the differences between the two parts, the differences were not major. Although discontinued from SERVICE in 1966, the GM #3832044 half shaft apparently continued to be used through 1974 to make up the GM #3847899 PRODUCTION half shaft assemblies used on all small blocks. I'm confident that the 3832044 was replaced by the GM #3872908 for SERVICE in order to simplify GMSPO inventory requirements.
It so happens that recently I've been able to acquire two NOS examples of the GM #3872908 half shaft, one of which suffers from very minor surface rust and the other from a little more extensive but surface-only rust. Both are unquestionably NOS GM pieces [not for sale]. I've had a chance to closely examine these. It does appear that the pieces were shot-peened with very small size shot. Also, the shot-peening was, apparently, performed after the half shaft yokes were welded to the tube during manufacture and the welds show no evidence of heat bluing. From experience, I know that shot-peening will remove weld bluing and, apparently, this occurred during manufacture of the the big block half shafts.
I have not been able to find any NOS examples of the GM #3832044 small block half shafts, which is not surprising since they were discontinued almost 36 years ago. However, I have studied the original half shafts on my original owner 1969 small block. These sufferred from very little rusting before I first restored them. On these, there is absolutely no evidence of shot-peening and the welds DO evidence the characteristic bluing caused by the welding heat.
One more thing: ALL 1963 through 1974 half shafts use a 2-1/2" OD tube. NONE used a 3" OD tube. The 3" OD tube half shafts are those originally used on 1975-79 Corvettes and which became the SERVICE half shaft for 1963-74 Corvettes when the GM #3872908 half shaft was discontinued in late 1975. These half shafts are GM #360912 and were manufactured by Spicer for GM. They are still available for a GM list of $159.95/each.
First off, folks need to understand that there were 2 ways that half shafts were supplied. Half shafts used for PRODUCTION were supplied to St Louis as complete assemblies which included both u-joints and the outside u-joint flange. So, the PRODUCTION part numbers were those for the assembly and not the bare half shaft. The half shaft assemblies, as used in PRODUCTION, were never available in SERVICE. Although u-joint part numbers varied from 1963 through 1966, the part number for the PRODUCTION half-shaft assemblies was not affected.
For SERVICE, the individual parts which made up the PRODUCTION assemblies were available. The part numbers for the pieces which made up the PRODUCTION assemblies were the same as those available in SERVICE.
PRODUCTION assemblies:
1963-only-----GM #3840317. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3832048 flange, and 2 GM #3823102 u-joints. It was used for ALL 1963 Corvettes;
1964----------GM #3847899. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3840318 flange, and 2 GM #3851520 u-joints. It was used for ALL 1964 Corvettes;
1965-1974 small block----GM #3847899. This assembly consisted of 1 GM #3832044 half shaft, 1 GM #3843018 flange and 2 GM #3877040 (1965) or GM #3889696 (1966-74) u-joints;
1965-74 big block-----GM #3882785. This assembly consisted of 1 GM #3872908 half shaft, 1 GM #3843018 flange, and 2 GM GM #3877040 (1965) or #3889696 (1966-74) u-joints.
SERVICE half shafts:
1963-1965 small block-----GM #3832044
1965 to March, 1966 big block----GM #3872908
March, 1966 to 1974 ALL----GM #3872908
The GM #3832044 small block half shaft was discontinued from SERVICE in March, 1966 and replaced, for all 63+ SERVICE applications, by the big block half shaft, GM #3872908. When both were last available in 1966, both carried the same GM list price of $17.30. So, that would imply that whatever the differences between the two parts, the differences were not major. Although discontinued from SERVICE in 1966, the GM #3832044 half shaft apparently continued to be used through 1974 to make up the GM #3847899 PRODUCTION half shaft assemblies used on all small blocks. I'm confident that the 3832044 was replaced by the GM #3872908 for SERVICE in order to simplify GMSPO inventory requirements.
It so happens that recently I've been able to acquire two NOS examples of the GM #3872908 half shaft, one of which suffers from very minor surface rust and the other from a little more extensive but surface-only rust. Both are unquestionably NOS GM pieces [not for sale]. I've had a chance to closely examine these. It does appear that the pieces were shot-peened with very small size shot. Also, the shot-peening was, apparently, performed after the half shaft yokes were welded to the tube during manufacture and the welds show no evidence of heat bluing. From experience, I know that shot-peening will remove weld bluing and, apparently, this occurred during manufacture of the the big block half shafts.
I have not been able to find any NOS examples of the GM #3832044 small block half shafts, which is not surprising since they were discontinued almost 36 years ago. However, I have studied the original half shafts on my original owner 1969 small block. These sufferred from very little rusting before I first restored them. On these, there is absolutely no evidence of shot-peening and the welds DO evidence the characteristic bluing caused by the welding heat.
One more thing: ALL 1963 through 1974 half shafts use a 2-1/2" OD tube. NONE used a 3" OD tube. The 3" OD tube half shafts are those originally used on 1975-79 Corvettes and which became the SERVICE half shaft for 1963-74 Corvettes when the GM #3872908 half shaft was discontinued in late 1975. These half shafts are GM #360912 and were manufactured by Spicer for GM. They are still available for a GM list of $159.95/each.
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