66 - Water Pump GM # 3859326

[Eddie H.]

I am having an almost impossible task of finding the correct dated water pump for my L79. I bought an after market replacement for the SB chevy. The fan pulley GM #3770245 doesn't mount correctly. The pulley makes contact with the front of the water pump. My question is. Is there a correct after market or GM/DElCO water pump with the correct fit and function available and from where?

Eddie

[Gary Schisler]

Re: 66 - Water Pump GM # 3859326

Eddie, others will chime in here with the correct information but are you sure that the date is judged? Relying on old brain cells here, but I seem to recall, for my 66 L-79, that the only thing that was looked at was the number as well as the size of the bypass hose fitting.

Just a thought,
Gary

[Gary Schisler]

Re: 66 - Water Pump GM # 3859326

Eddie, others will chime in here with the correct information but are you sure that the date is judged? Relying on old brain cells here, but I seem to recall, for my 66 L-79, that the only thing that was looked at was the number as well as the size of the bypass hose fitting.

Just a thought,
Gary

[John H.]

Re: 66 - Water Pump GM # 3859326

That date isn't judged, as it's not visible with the pulley installed.

[John H.]

Re: 66 - Water Pump GM # 3859326

That date isn't judged, as it's not visible with the pulley installed.

[Eddie H.]

Re: 66 - Water Pump GM # 3859326

Even with the date not being an issue. Finding the 326 seems to be like looking for a needle in a haystack. I am looking for correct functionality for the time
being. Meaning correct fit.

Thanks.

[Eddie H.]

Re: 66 - Water Pump GM # 3859326

Even with the date not being an issue. Finding the 326 seems to be like looking for a needle in a haystack. I am looking for correct functionality for the time
being. Meaning correct fit.

Thanks.

[James W.]

Re: 66 - Water Pump GM # 3859326

Eddie,

I just installed a correct pump on my L79 equipped '65 coupe. I put a "wanted" ad in the driveline and received a few calls/email from fellow members that had "326" pumps for sale. I bought one and had it drop shipped to Bill Mock in Oklahoma for a rebuild. When I went to put test fit it, my water pump and crank pulleys did not line up exactly right either. I simply took the pump back off the car and removed the back pump cover, supported the impeller and shaft and pressed the hub onto the shaft a little further to get the pullueys to align. In you case you can either buy the reinforcement/spacer that goes between the water pump mounting hub and the pulley to shim the pulley out away from the water pump body OR use a small 3 or 4 jaw gear puller to pull the hub away from the pump body. There is a GM water pump pulley reinforcement/spacer up for auction on EBay at this time, auction #320181524041.

I also have another "326" water pump but it is a mid 1967 dated pump AND it has the larger 5/8" diameter bypass hole that was standard for I think pickups of that era. I have a 5/8" diameter to 1/2" reducer bushing that can be installed to make the correct 1/2" diameter bypass elbow work. You with the correct part number water pump with the incorrect diameter bypass port should only get you a 2 or 3 point deduct for originality instead of 25 points for a pump with an incorrect part number. If you are interested it is your for what I paid for it; i.e. cheap.

Hope this info is of some help to you.

Best Regards,

James West
Omaha, NE.

[James W.]

Re: 66 - Water Pump GM # 3859326

Eddie,

I just installed a correct pump on my L79 equipped '65 coupe. I put a "wanted" ad in the driveline and received a few calls/email from fellow members that had "326" pumps for sale. I bought one and had it drop shipped to Bill Mock in Oklahoma for a rebuild. When I went to put test fit it, my water pump and crank pulleys did not line up exactly right either. I simply took the pump back off the car and removed the back pump cover, supported the impeller and shaft and pressed the hub onto the shaft a little further to get the pullueys to align. In you case you can either buy the reinforcement/spacer that goes between the water pump mounting hub and the pulley to shim the pulley out away from the water pump body OR use a small 3 or 4 jaw gear puller to pull the hub away from the pump body. There is a GM water pump pulley reinforcement/spacer up for auction on EBay at this time, auction #320181524041.

I also have another "326" water pump but it is a mid 1967 dated pump AND it has the larger 5/8" diameter bypass hole that was standard for I think pickups of that era. I have a 5/8" diameter to 1/2" reducer bushing that can be installed to make the correct 1/2" diameter bypass elbow work. You with the correct part number water pump with the incorrect diameter bypass port should only get you a 2 or 3 point deduct for originality instead of 25 points for a pump with an incorrect part number. If you are interested it is your for what I paid for it; i.e. cheap.

Hope this info is of some help to you.

Best Regards,

James West
Omaha, NE.

[Eddie H.]

Responded by e-mail *NM* *NM*

[Eddie H.]

Responded by e-mail *NM* *NM*

[Gary B.]

Pulley reinforcement; GM still sells it

James, Eddie,

GM still sells the reinforcement (3720616) for a list price of $3.00, so don't be fooled by an e-bay seller who gives the impression that an old part in an old GM package is worth extra for something that you won't be able to see when installed.

Gary
NCRS Northern California Chapter

[Gary B.]

Pulley reinforcement; GM still sells it

James, Eddie,

GM still sells the reinforcement (3720616) for a list price of $3.00, so don't be fooled by an e-bay seller who gives the impression that an old part in an old GM package is worth extra for something that you won't be able to see when installed.

Gary
NCRS Northern California Chapter

[john daly]

Re: 66 - Water Pump GM # 3859326

Were the 326 pumps with an S cast(saginaw)used in corvettes?. I found one with the 1/2" npt bypass fitting recently at a swap meet.

A few years back a friendly counter guy at a large chain auto parts store allowed me to sort through a few of the rebuilt pumps in stock. I found a 326 casting pump with the larger bypass hole. I used a non hex head type bushing to get to 1/2" and ground it down a bit and used some permatex and a heavy coat of orange. I know i'm not fooling anyone who looks closely but it looks better to me.

john

[john daly]

Re: 66 - Water Pump GM # 3859326

Were the 326 pumps with an S cast(saginaw)used in corvettes?. I found one with the 1/2" npt bypass fitting recently at a swap meet.

A few years back a friendly counter guy at a large chain auto parts store allowed me to sort through a few of the rebuilt pumps in stock. I found a 326 casting pump with the larger bypass hole. I used a non hex head type bushing to get to 1/2" and ground it down a bit and used some permatex and a heavy coat of orange. I know i'm not fooling anyone who looks closely but it looks better to me.

john