Did you try the 87 tune yet? Considering doing this have a tune on my mustang set for 93, but with 80 mile commute and gas prices may take some timing out to run 87 or 89. Truck is not together yet but also thinking about putting a boss intake on it looking for a used one as prices have jumped up on these.

 

I had a 2000 Lightning with 3.55, gears completely stock and it turned 13.99 100 mph, so you time is very respectable.