1966 Barracuda w/273 w/AC is the Water pump diff between AC and not? Napa says there is other parts places do not show diff.
What's the real story?
Thanks
Rick

if there is a difference it'd have to be the vane count. I'd have NAPA pull what they got but if there is an 8 blader that would be my choice (& an anticav plate especially if only 6 blades is offered)

They have to order the AC one, so I guess since this car has AC and NAPA is the only one to offer an AC pump.....I have little choice.

an AC pump will have 6 vanes & that is on a '70 up alum pump (8 for non AC). they speed up the pulley ratio to 1.33 (iirc) for more air and water flow at idle/above & is needed with the AC on) but this can make the pump cavitate at higher speeds with the higher ratio so they dropped the vanes to 6 to deal with that but you still get enough flow at lower speeds due to the higher ratio. With what we know now, go with 8 vanes (non AC pump) for more flow and add the anticav plate for the best of both worlds but with the pre '70 iron pump possibly only 6 vanes are offered so you might not have a choice. I would see if they can confirm one way or another & if you have a choice I would highly suggest 8 vanes+the plate

I looked at the offerings at Rockauto for a 66 Cuda, 273.

Everyone of them had 8 vanes,only one offering mentioned AC at all and it was for non-AC. So I dunno the difference, none of them had anti-cavitation plates on them stock, you can get them on the 70 and up pumps though.

that is good news that you can get an early iron 8 blader. I'd add the plate & you might not even be turning it high enough to get into cavitation (& not sure what ratio you have) but it is an easy and worthwhile addition to do. last one I did I cut a circular piece out of a washing machine panel with the OD slightly less than the OD of the vanes so my welder could tack it to several of the vanes & a hole in the center to weld it there also. first I pressed the vanes closer to the pump body (.030") & support the shaft on the other end when doing this & I would put feeler gauges between the vanes and the body as it might jump on you when doing the pressing (all this not likely needed in a DD) but it does make for a very efficient pump (& also reducing the vane to t cover flat to .030 (account for gasket)

I have an NOS Iron pump if you're interested.

- EM