Hello all! It's been a while...
So, I pulled the 194 from the Nova... 250 is in! As I'm buttoning things up, I found the fan bolt pattern on the 250 is larger than that on the 194! I have a pump with both bolt patterns, so I pulled the one from the engine... the impellers are different! The one has a plate on the back side covering the impeller. The one that came off the engine, the impellers are curved the opposite direction!!!!!!!
Are there engines that spin the water pump in the opposite direction? Should I install the dual pattern pump?

That sounds weird, maybe one of those pumps is off of a marine engine? You got me, but i'm running a flowkooler pump on my 194.

Don't use it. It'll still pump but it'll be at a greatly reduced flow and pressure.

I'm a manufacturer's rep for water and waste water pumps. We see pumps running backwards all the time and they do "work" sort of for the most part as long as they're centrifugal (like your car water pump). That said they don't work well that way.

Can you swap impellers?

Over the years, I noticed that most engines with v belts have pumps that turn clockwise.. With serpentine belts the pumps turn counter clockwise.. Something to keep in mind.