Installing some IMCO SC lowers on my XR drives and wondering the purpose of splash plates are above the propellers? I was told some guys do not run them. Do they just lesson rooster tail or do they actually do something else?

^ This is what I was told by George at All American.

If you made the unit without 'em when you put the unit in gear water starts heading for the prop from all directions . You'd even get a vortex on the surface like water going down a drain.
They're actually 'anti ventilation plates' to stop the prop unnecessarily ventilating . The word 'cavitation' is very commonly used incorrectly .

Makes sense to me. Thanks for the info! I will order the plates now.

OK , I'm a bit puzzled . How do you order them and put them on ? If we are talking about the anti-ventilation plate(s) they're an integral part of the lower unit's structure and are all cast as a one piece casing when they're made. I woulda thought you either have them or you don't .

Pretty sure he’s referring to these pieces, splash plate

I tried running a 4 blade bravo on my Outlaw without one and it’d blow out every time trying to plane.