In my first post I only saw your last run (the one with the 2.5 60'). The 2.2 60' on street tires isn't that bad at all, but I'm sure you could still improve it.
With a 92 vert, full exhaust and 4.10's, you should be able to lay down some really low 14's on a good weather day.
I wouldn't just dump the clutch with street tires - way too much tire spin could result. Try the slip-of-the-clutch method and see how you do. Also, are you powershifting? Speedshifting?
E
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1991 5.0 LX Coupe - 38,000 miles
13.17 @ 106.14 mph w/ 2.138 60'
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