Better to put it here so we can shit on your thread.
Mercury makes a prop called the REV4? I not questioning, just never heard of it.
Mazco make a R.E. 4 -
http://www.mazcoprops.com/images/re4prop.jpg
BTW - my friend with an Allison and a Viper really likes his trophy. That what he runs most of the time on his GS/260 combo.