Description

This is a Brand New water pump with gasket for a 401 and 425 cubic inch Buick Nailhead engine. This water pump will fit 1962-1966 Nailhead engines. This is a 5 blade water pump which is technically correct for air conditioned (AC) vehicles. It will work fine on non AC vehicles as well (non AC vehicles had 3 blades).

This water pump has a composite plastic impeller as shown in pictures 2-4 in the listing. The manufacturer has recently changed the manufacturing of this water pump to include a composite plastic impeller, they will no longer be making these water pumps with cast iron impellers. The last picture in the listing shows the new composite plastic impeller on the left versus the cast iron impeller on the right. The new composite plastic impeller looks very nice and in made to the same specifications as the old cast iron version.

I have done a fair amount of research on this change to a composite plastic impeller rather than a cast iron impeller. The failure point of a water pump is typically the bearing. If the bearing starts to fail the impeller will start to wobble. When the impeller starts to wobble it does not spin in the tolerances between the water pump housing and the timing cover. The impeller could then start to hit the aluminum timing cover and cause damage. In the cast of a cast iron impeller it could do significantly more damage than a composite plastic impeller since the cast iron is harder than the aluminum on the timing cover and could wear grooves into the aluminum of the timing cover, for example. Whereas the composite plastic impeller would break and do less damage to the aluminum timing cover. That is just one opinion however on the composite plastic impeller. Another issue people have mentioned in the past, is the composite plastic impeller could spin on the shaft of the water pump. When looking at these new composite plastic impellers there is a metal hub in the center of the composite plastic. I do not believe this would have any issues with the impeller spinning on the shaft. Overall I do not see any dis-advantages to the composite plastic impeller. I am more than happy to answer any questions on this manufacturing change and on the impeller.

If you need any other Nailhead engine parts please see my other listings or ask. Please ask questions.