Got some baselines at the 1320 now some help

after you get your fuel issue solved i would look into the following based off how the car performs.
Call hughes and tell them what your trap RPM, gear and tire size is (as well as car weight engine specs ect.) and and find out if 10 to 12% slip is ok? i think you will want something more in the 5-7% range. See if they can tighten it if needed. If your unit is making more power than what they used to come up with that stall number you may actually be stalling at a close to 4500 and the unit my be "loose" past that. I dont think the verter is the main issue just another piece that could be addressed.
I think you need to go to a bigger gear. if it doesnt loose power unitll 6800 you need to be trapping at about 7000+. With the gear you have right now you are using up too much 1/4 mile rel estate in a lower transmission gear. You need to be in 1 to 1 sooner so that you trap closer to 7000+. I have a hunch that after you solve the fuel issue if you shifted the car at like 6200 with that current gear in the back the car would run faster both ETA and MPH. I personally think changing your gear will give you the most results because even if you have 10%+ slip you still are not trapping in the RPM range that it should based off what you said the engine did on the dyno.