Hello folks. I was last on the site June 24th (hangs head in shame), and have had my head buried in our new Business Computer System migration, so didn't notice the callout right away, sorry about that. There will be follow up to come, and your contact on these forums, James@TheZStore will jump in (you can always ask him whatever you need, he'll take care of you).
My nephew and I took that image back in 2008, lol. I honestly wasn't aware of the impeller debate, perhaps I should get out more. I think he asked me whether to take a picture of both sides, and I couldn't think of any reason to show the bottom... Tony D can knock me in the head for not knowing when he next sees me. : )
Obviously I've read both sides of the debate now, and see good points for each. Unfortunately the top brand out there, Paraut (cast impeller) has been discontinued. Our supplier did find likely the last three remaining new (that he can find anyway), and they are up at the store (the cost kicked the price a bit, but still less than Amazon, and I doubt they can get them any longer. Just use the link Zed Head has above). If any of you order one of those last three let me know here after you order it and I'll get you a break on the price (limited to the 3 we found). I am currently looking for another "premium" water pump to replace the Paraut. James will let you know what we find in Japan.
We also switched to a better supplier on the regular water pumps (GMB at the moment), which are still good quality, just with stamped impellers, and were able to drop the price way down. Greg (the Z expert here) was familiar with the debate, and noted to me that they have good points as well, since the stamped impellers are lighter and less of a load on the bearing, and the fin surface area is usually larger than on the cast impellers, and move the same volume of water as the stock units. I'm sure the debate will rage on though. I think I'd be comfortable with either on my 71, which I'll probably need soon anyway. I might go with an electric one if I can save a few beans up. Guess I should get it running right and not burning oil first, lol.
Thanks for your patience with slow responses and slow fixes, which is especially that way as we finish the mega-task of migrating our old Unix system to a whole new bright and shiny one. Hopefully the new store that is being redone at the same time will be worth the effort.