[John V.]

If the "strange" impeller is stamped steel, I suspect a remanned aftermarket pump. If no PMD p/n cast on the pump body, I suspect the whole thing was an aftermarket replacement.

The 9772716 body casting indicates a '63-'65 Pontiac pump.

Hard to tell, but the vanes on the impeller look shorter than the vanes on the impeller that Chris posted earlier.

If they are the shorter vanes, then the pump was for the '63 4 cyl (2nd design timing chain cover, I think the early cars used a 4 bolt pump?)

Measure the vanes and you'll know for sure.

I'd have to look back at my early research but my recollection is that the vanes for the V8 were 3/4" high. Don't take that as gospel, just going by memory.
The 4 cyl vanes were noticeably shorter. Just to satisfy my own curiosity, look closely at the front of the 9772716 pump shaft to see if any nos. are stamped on it.

[Jack P.]

Originally Posted by John V.

If the "strange" impeller is stamped steel, I suspect a remanned aftermarket pump. If no PMD p/n cast on the pump body, I suspect the whole thing was an aftermarket replacement.

The 9772716 body casting indicates a '63-'65 Pontiac pump.

Hard to tell, but the vanes on the impeller look shorter than the vanes on the impeller that Chris posted earlier.

If they are the shorter vanes, then the pump was for the '63 4 cyl (2nd design timing chain cover, I think the early cars used a 4 bolt pump?)

Measure the vanes and you'll know for sure.

I'd have to look back at my early research but my recollection is that the vanes for the V8 were 3/4" high. Don't take that as gospel, just going by memory.
The 4 cyl vanes were noticeably shorter. Just to satisfy my own curiosity, look closely at the front of the 9772716 pump shaft to see if any nos. are stamped on it.

The shorter vanes are shorter to avoid cavitation, if you look at the curve, it goes the opposite way scooping instead of pushing across the back of the curve.

[John V.]

Jack, not sure if I follow your point. Both the V8 and 4 cyl pumps assembled with the 9772716 pump body used the same "style" impeller. The shorter vanes used for the 4 cyl moved less water.

By ht., I mean how much the vane rises off the impeller face, not the length that they extend from edge toward center (they both are same length and shape in the regard.

Using a 4 cyl pump and original impeller in a V8 may result in less flow and hotter temps.