Hi all,
Water pump - need help
I have a 1971 cutlass with what is likely a 1972 350 2 BBL engine. The water pump has failed. The current pump I removed has a 5.1" measurement from the from Block Mounting to Pulley Surface. In my extensive search (NAPA, Summit, partsgeek, sixity, Auto Zone, O'Rileys etc) the parts that claim to fit measure either 5.5" or 5.9".

Pump casting reads:
408 328Y
D6

NAPA #43100 is 5.9" and #43107 is 5.5" - NAPA source indicated 350 engine water pumps were the same part from '71-'80
Airtex-AW773 per supplier specs is 5.5" and 5.9"

Can someone assist and help me find a 5.1" water pump or offer other solutions?

Thanks,
Ken

 

Can you tell us what accessories you have, like AC and power steering, and can you tell us what block it is? It's a casting code right behind the water pump on the engine, immediately to the driver's side of the oil fill tube. Should be six or so little numbers then one big one.

 

Accessories: Power steering
No AC or PB
Block casting # 395558 2
Pulley has two belt grooves and is 4 1/4" in diameter. There is a 2 1/16" spacer
Thank you.

 

The 408328 is the correct water pump for non AC non HD applications in 1971-72.
The factory specs are 5.072 inches.
You have the correct KN pulley also by the way.
I have a rebuilt 408328 water pump available.
I would want $200 plus shipping.
Thanks

 

You will learn that just about every single catalog lists Oldsmobile water pumps incorrectly. Airtex 773 is a 5.1" pump - I have one on my 67 Delta. The problem is that it uses the large hose inlet diameter for the 1970-older motors. Airtex 773 is equivalent to OEM P/N 384783 (casting no. 388182). Unfortunately the 5.1" P/N 408328 pump with the small inlet (casting number 231065) was only used in model years 1971-72 without A/C or HD cooling and is not readily available from replacement sources. You can have yours rebuilt, buy a correct rebuilt one, or use an early pump like the Airtex 773. The latter option will require you to use a 1970 lower radiator hose and bushing to adapt this larger hose to the radiator outlet.

 

The info on the 408329 is a little incorrect.
That number is the casting number not a part number.
It is also not 5.1 inches, it is almost 6 inches for shaft length.
It is also the HD water pump for 1971-72
The standard short shaft is 408328.
The AC long shaft is 407586.
These are the casting numbers.

 

This may help.Flowkooler 1575 5-1/8” Height


.FlowKooler introduced the first hi flow pumps and continues to improve impeller design. Why is increased flow so important to cooling a hot Olds Rocket engine? Because it has been proven time and time again that reducing the cycle time between the heat source and the heat sink creates more opportunities to shed heat and drop engine temperatures.

From 0-3,300 RPM…Nothing Beats a FlowKooler!

General Specifications:

Number of vanes on impeller

16 CNC Aluminum

Direction of Rotation

CW

Fan hub working height
5-1/8" non ac cars

Shaft Diameter

5/8"

Inlet Outside Diameter

2 1/8"

Hose Connections:

1st

2nd

Gender

M

M

Diameter

3/4"

3/4"

Threaded

No

No

Other Special Features:

• 16 blade CNC Machined Aluminum impeller
• Impeller protected with a military grade Type II anodized surface coating
• Has two male 3/4 heater hose connections
• Commonly called a "short pump" for Oldsmobile.
• Fits 1960s and 1970s GM products without AC
• Alternative Part Numbers 230336, 230608, 230899, 384783, 384786, 388182, 388183, 398681, 404584

Thirdcoast

 

Note that the FlowKooler pump above has the larger diameter lower hose nipple that is correct for the 1970-older engines and not the smaller diameter nipple that was used on the 1971-newer engines.

Joe P pointed this out in his reply:

 

I used one of those adapters to bush the the hose to the rad outlet on my car. I was concerned that it might not be that robust a solution but it been several years w no issues so i endorse it.

in short you could get the airtex 773 a new lower hose to fit that pump and the reducer to fit the new lower hose to your rad

i found the reducer on amazon but im sure you can get them multiple places

 

408328 is standard 71 - 72 issue pump with 4.8 dia impeller & 5.1 flange height ( gasket - pully)

Typicaly has big #1 on casting above inlet

Let me know if you need some

 

I'm hoping that after two years the OP has figured this out.

 

 

Despite what other people have written, I can tell you from first-hand experience that the AW773 is a 5.1" pump. I just installed one on my 68 Cutlass wagon two weeks ago.

 

I believe I have an original rebuilt 408328 water pump available.
Thanks

 

appreciate it