I was kinda hoping you'd remove the water pump altogether for testing, but I forgot that you are using the stock alternator mount that incorporates the WP. I really wouldn't suggest that you take-off without an alternator as this is not only an unnecessary risk, but also wouldn't provide any realistic test data. The pump can provide much greater flow when supplied with 13.8 volts than it can at <12 volts.  

 Good point Todd. 

All this talk of dual EWP's has forced me to look at the possibility again.  One thing that would save me a lot of work would be to keep the water pump housing.  I could just remove the pump, and put a plate over the opening.  Keeping the housing would preserve my water inlet, outlet, filler cap, temp senders, and alternator mount.  Then it would "simply" be a matter of installing the second EWP, making new fittings, and changing the hoses.  I'll take the other EWP back to the hanger today to stare at it some. 

Cheers,

Rusty (go goon girls)