With my 4.6 I can get in the low 8's but I do most of my tests with near full fuel. I bet I could get into the 7's if I did it below a 1/4.
When doing these I have a hard time keeping the tires from breaking loose.
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2004 XLT SCAB / 4.6
Current: In bed lighting, K&N Drop-in, Gott's intake mod, Gryphon custom tuned
Future: Exhaust (next), UDP, eFans