Bruce,

You've hit on one of the main problems in getting good times after having
upgraded a Xfire. All that torque doesn't make for good 1/4 mile times if you just sit there and spin the wheels. Like yours, mine is setup for road driving and not 1/4 mile runs. Full Z51 suspension and running 35psi in the tires with a 3.07 rear. It seemed that my best 60' time came leaving the line at about 1700rpm running it up to redline and then shifting to second whether the tires were still spinning or not.
The second is topend with the fuel curve leaning out past 4000rpm. I am looking to address the top end, because after the 1/8 mile, the motor starts going flat. Using a wideband O2 sensor on a dyno, what AFR did you target
at WOT? I have been told it should be somewhere around 12.5:1 through the HP peak.