im now getting any oil pressure on my 98 ev motor!

[sdcr]

At the risk of sounding very naive, how does one determine which way is upside down?

determine if the pan gasket hasn't been installed upside down.

It's easy to do.

don't ask me how I know.   

[rodekyll]

The other way doesn't match the oil holes.  I hate it when that happens.

[troyhamilton]

it was a 100 degree day when i put it together and i wasnt wearing my glasses. nuff said.

[LowRyter]

At the risk of sounding very naive, how does one determine which way is upside down?

what RK said.

[Tom]

I bet the glasses for the optically challenged has something to do with it.    Sweat in the eyes while working on something will have a negative impact.   BTDT.    Feel your pain. :1:

[Kiwi_Roy]

Sure there is: right near the oil pressure switch, down on top of the engine case. Or just remove the oil pressure switch and see if oil squirts out there.

Banjo bolt right at the "Y":

An easy way to plumb in a gauge is to attach a second banjo on top of the one that's there, drill out a longer bolt with an extra set of holes to match.
I mounted the gauge for my Eldo and the California II onto the crash-bar so it doesn't need to be flexible, plumbed with copper tube.