Basically you need to put in 1.8 Gallons of your 100 for every gallon of 87 in order to give you 96.

Dean, The Exxon station at exit 11 (John Puryear highway) has 110 octane. I use it on special occasions to spruce things up a bit in my boat. I also add some to my tank at the beginning of each season just in case the 93 lost its punch over the winter hibernation.

Tony