yes pull the foam out of the tank....it will disolve and plug up regulators and ruin pumps. as long as your running carb...yes tank in the rear is fine. if you ever go to injection you can make it work but the best way is mount tank if front. you have to have a fuel pressure regulator designed for alcohol. same deal with fuel pump. keep in mind running alcohol uses twice amount of fuel and if its a larger engine which requires more fuel, you may want to up the size of the main line from the tank to the regulator and possibly up to the carb too.