swapping 5speed to Auto for race purposes only

With SS suspension it only takes a P/W of about .107 to "CRACK" the 12s and get an 11.99. With you and the Swinger weighing a max of 3400, that would be 367 HP.

If you have 400hp and 3400 pounds , that would be a PW of .1176 which is an 11.7 potential. At 12.72 you are dead on for a 1 second loss in the suspension.
In which case, to get an 11.99 with that suspension, you might need 455hp
Which one to fix I guess is up to you.