Paul

It seems your pump fits my criteria for a central inlet. That is good news.
To clarify our discussion I've included a picture of Ed's modified pump fit
on the block for comparison with your remote design.

Your design eliminates the abrupt and torturous route the water must travel
and that alone will improve the pumping rate.  I also see you have tested it
using your end mill set up. Am I correct in guessing you use the standard
Mazda impeller?

The design structurally looks very good.  If it is a better performer than a
modified Mazda pump I am definitely interested in purchasing one. I
understand it still only a casting and needs some machining to finish it.

DougFir

The pictures you attached are my pictures? Ed who? :)

Straight in inlets are definitely more efficient than
the Mazda style right angle input. I notice Jim Mederer modified
the KSE pump for a straight in inlet. If you butcher
the stock 2nd gen 13B pump correctly you can add a straight
in inlet. Cut away everything inside the red line and weld
in a straight hose barb represented by the blue circle.
You now have a remote pump. Half the stock pump is merely
a glorified hose barb for the water coming out of the block.

Yes my remote pump uses a stock Mazda 2nd gen replacement cartridge.