http://www.fuel-testers.com/marine_boat_ethanol_problems.html
http://www.evinrude-parts.com/boat_ethanol_danger_precaution.html
http://www.consumeraffairs.com/news04/2008/04/ethanol_class.html
The links go on and on. Remember E85 is 85% ethanol (alcohol). Alcohol will absorb tons of water, especially in a high humidity environment such as in a boat. Your fuel line will have to be replaced with something other than rubber, which will not be coast guard approved.
Also will that gas station by your house follow you around? The closest to alum is the Meijer on 23, your looking at a minimum of an hour to refuel from pulling out to dropping in, barring no ramp traffic or other cars on the road. Erie, no idea whats close there with E85. Cumberland, I know nothing between Renfro Valley and the lake has it, so your looking at over an hour drive each way, plus time to put it on the trailer and unload. Not sure what power the motor is going to make this go around, but FYI a HP500EFI will burn 42GPH at 5200. With the stroker you have, I was running through 2-3 tanks a weekend at alum.
With the cometic head gaskets going .120" now, you can drop almost a point of compression, go with those and run straight gas and forget the headaches. Been there and ran specialty fuel in a boat, never again.
Cred05 and thorne, you are big E85 guys, how fast are your boats running?