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Re: 66 - Water Pump GM # 3859326
john-----
Yes, the '326' waterpump castings were used in Corvettes. I expect that all that were used for Corvettes were cast at Saginaw. However, I don't know that all of these ever had an "S" foundry mark. Some did, but I don't know that all did.
The '326' castings were used for SHP small blocks (i.e. with aluminum manifolds) from 1965-67. According to some accounts, they may also have been used as early as 1963 for SHP small blocks. I doubt it but I wouldn't completely rule out the possibility.
The '326' castings used for Corvettes had the bypass fitting tapped for 1/2" NPT. Many later examples of the '326' are tapped for 3/4" NPT. Bushings are commercially available to reduce the 3/4" to 1/2". Properly and cleverly installed and after pump painting (all small block pumps were painted with the engine), I would defy anyone to discern that a bushing was installed.
john-----
Yes, the '326' waterpump castings were used in Corvettes. I expect that all that were used for Corvettes were cast at Saginaw. However, I don't know that all of these ever had an "S" foundry mark. Some did, but I don't know that all did.
The '326' castings were used for SHP small blocks (i.e. with aluminum manifolds) from 1965-67. According to some accounts, they may also have been used as early as 1963 for SHP small blocks. I doubt it but I wouldn't completely rule out the possibility.
The '326' castings used for Corvettes had the bypass fitting tapped for 1/2" NPT. Many later examples of the '326' are tapped for 3/4" NPT. Bushings are commercially available to reduce the 3/4" to 1/2". Properly and cleverly installed and after pump painting (all small block pumps were painted with the engine), I would defy anyone to discern that a bushing was installed.
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