Poly Fuel Tank

[Hoover]

I want to replace my aluminum tank for a larger poly tank a friend gave me. Problem is the only way it will fit is if it is mounted right against the hull. Is this a problem?(It is a 55 gallon tank from todd w/no baffles.) The old tank is 30 gallon aluminum that sat on a glass/over plywood base that kept it elevated off of the hull. Just looking for opinions/advice. Thanks