Don't know why people keep saying 6 degree beam. I think they have been brain washed by people that sell 6 degree beams like its some sort of magic number.

For pure 1/4 mile times you would want a 0 degree beam so fully trailing arms not semi. This way the camber will not change.

To improve it further you could install a de dion tube to effectivley to link both independant arms and convert to solid axle.