My guess is 7.25/97 on the motor and 6.85 on the spray, maybe better. My fish with the pump gas 416 ran 7.20 at 98+ weighing 3150 with 3.91s. The 60 was 1.65 on 275/60 DRs on a prepped track with leafs and sh*tty shocks and a POS vert.
I don't follow the logic of the rear line lock, but when you get into the water box you'll see if it works. IMO the LL is to hold the car as the tires heat up before you blast out toward the line with the lock disengaged and the throttle mashed. Don't forget to get a pill that works when the LL is engaged and then another that kicks in when it is turned off. My MSD 7AL-3 has 3 pill slots which I have set LL (burnout), TB (launch), race. Then there is the timing retard for boost / juice which is separate.
The exhaust sounds great. Only thing I might change is to put a 8" cherry bomb and dumps on each side at the axle and run the rest of the ex back from the dump, so when the engine is loafing/idling all the flow goes straight back and when on the gas the back pressure of the rear exhaust forces the flow through the dumps. But that would add weight. Old Man Mopar posted a pic of his ride with that setup.