If you send in film without their request, they will use it to tape practices and there is very little chance they will actually watch it - so says my buddy who walked on 1999-2003.
With those credentials surely you were recruited by somebody if not LSU or another major D1 program. You might want to get in touch with Coach Saban and the coach who would would be your position coach to at least make them aware of your existence. Walking on can be tough and they will probably use you to hold the blocking dummies in practice for at least a couple of years and as a walk on it would be tough to get enough practice reps to show what you can do and to build continuity and unity with your teamates. You might want to consider playing for a junior college for a year or so and then transfering to LSU. That way you could gain experience and if the coaching staff is aware of you before you do it they will watch your progress whether you are aware of them doing it or not. Whatever path you take I hope that one day I see you wearing the purple and gold in Tiger Stadium. Good luck to you .
Itsn't your coach Barry Wilson who played and was an All SEC player at LSU? If that is correct I would think he would make a call for you and that they would listen. A friend of mind named Danny Hurstell, who played center of Holy Cross from 70-74 walked on at LSU and stayed on the team for 2 years before giving it up due to the fact that he Tiger Bait and couldn't take the pounding any longer. He wasn't near as big as you though, about 6" 235 or so.