Im new forgive me if im in the wrong section but i have a 1966 mustang coupe and just took out the rusted gas tank and will be replacing it. I want to put in a 1969 20 gallon tank. I have two questions. Is 1969 the 1st year the 20 gallon tank was available? and how will this effect the mounting of the tank? i am aware that it will sit higher but will i need to do any modifications for tank to fit properly?