I'd do the head swap and see what that gains you. If you still need a little more ET I'd get a better/looser convertor. When my car ran 7.0-7.1s my 60ft was typically 1.51-1.53. I don't think you'd seen a big improvement from 1 7/8 to 2" headers. I went from 1 3/4" TTI to 2" hooker fenderwell and I might've picked up a tenth if I"m lucky in the 1/4. I have a .040 440 10.9:1 MP .557 cam, Trick Flow 240, Victor Intake, Proform 850, 727 with 5000 stall 8", Dana 4.56 using a 30" tire. Car weights 3200lbs with me in it. Best it's been is 10.49 @ 126, but typically a 10.60s car.