This link
http://tinyurl.com/d3qj5f

has this text

Powerhorse pump requires 5.5 HP engine with 2 7/16in.L, 3/4in. straight
keyed shaft, 5/16in.-24 tapped hole and 3 5/8in. bolt circle.

Very similar to the Pacer Pumps I use for high volume applications:
http://www.dultmeier.com/pdfs/prSser2.pdf
Note the straight shafts on all the different mounting and drive methods
including electric motor drive.

I am quite familiar with pool/spa pumps, have two complete 1-1/2 hp
pump/motors and two spare motors in the stock room. These have straight
shafts with left handed nut to hold the impeller on.

Bruce L. Bergman wrote:
On Sat, 04 Apr 2009 21:02:46 -0500, RoyJ
wrote:
Bruce wrote:

This style pump head is meant to direct-mount onto a certain tapered
crankshaft tail normally found on gasoline engines - which you are NOT
going to find on regular electric motors. The pump impeller has the
female of the tapered shaft with the lockbolt, and the tolerances when
it's all bolted together is critical.
The OP listing clearly states "3/4 inch straight shaft with keyway"

O Rly?

I read the eBay listing referenced as a tapered shaft with an end
hole for a lock bolt. Sure you looked at the right page? They :do:
come both ways.

-- Bruce --