Hey guys, Just pulled the motor out of my 69 Cutlass S for various reasons. It's a brand new remanufactured 350 rocket with less than 500 miles on it. Everything is stock in the motor except for the cam. It has an old oil pump on it and an old water pump. They are not new. I want to replace them while the motor is out but not sure if they should be replaced with standard or high volume parts. Also have a brand new vintage air AC system as well. All suggestions are appreciated, thanks!

 

Standard should work fine. Be sure to match the water pump to your current one - there are three different snout lengths depending upon application and two different hose nipple diameters depending upon year (71-up is smaller than 70-older).

 

I prefer high volume oil pumps. You should still be able to find GMB aluminum water pumps.

 

If the engine is new and stock, with tight clearances, a high volume pump will offer no benefits, as the extra volume will just be shunted through the relief valve back into the oil pan.

It won't hurt anything (except maybe by taking a couple of extra horsepower), but it won't help either.

- Eric

 

GMB? What's that

 

 

A standard oil pump is all you need. A High volume pump will just put more stress on your distributor drive shaft and rob horse power.

A GMB water pump is aluminum vs. the stock cast iron unit. Last I heard, they're not being made any more. Oldsmobile is a small market.

A google search will tell you if one or any is still available for your engine. Or search your favorite parts provider. You might find one in stock

 

I suggest a parts store water pump. It will have a warranty on it which might come in handy.

The oil pump is your preference. As the others said, there is no need for it; however, since you have the engine out and are taking off the oil pan you Might As Well get it done.

 

I agree. My engine has a regular parts store reman water pump with the stamped steel impeller and the engine doesn't run hot in our 110+ summer temps.

 

Rock auto had gmb pumps two weeks ago when I was looking. Summit racing listed high flow GMB and others. After looking at the impellers, I went with the Flowkooler. It has an aluminum two step impeller. How much better than stamped steel, who knows. I see a lot of gap between blades on the parts store reman i took off, but again, not being a mechanical engineer or hydraulisist, my opinion is just that.
Tim

 

I agree the stamped steel impeller is not the best design. When my water pump needed replacing a few years ago I did a lot of research. Looked into having a factory pump with cast impeller rebuilt, actually bought a Flowcooler pump but sent it back cuz I didn't like the housing design, finally just bought a reman from the local parts store. As I said, it cools fine in Phoenix summer heat so apparently the inferior impeller is still capable of adequate coolant flow.

 

I've been working on my own stuff for quite some time now, and I can't recall ever having to warranty a water pump.

 

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