Don't know what I'm doing

Racer Dudes,

Last year I started "racing" my Duster. Just going to test-and-tune nights for fun with the guys.

Setup:
340 - dynoed at 458HP
4 speed
Centerforce Dual Friction
Line lock
002/003 SS springs
No pinion snubber
NAPA shocks on front
Monroe shocks on rear (from Mancini for SS springs)
Hoosier DOT drag radials P275-60-15

First time out, best was a 12.94 with a 3.55 gear. Next time, best was 12.77. Borrowed a 3.91 gear and got down to a 12.49.

This year, I went to a 4.30 gear which is a good gear, I think. I'm around 6000RPM through the lights. My 60' time is not good, though. I made a few runs and eventually ticked off an ET that made me smile. On this particular run, I revved to about 3500, then before dumping the clutch, I floored it. My buddy says I smoked the tires for quite a ways - I didn't know they spun that much... I didn't speedshift this run. Anyway, here are my numbers. Not concerned about reaction time yet - just working on my driving.

RT .423
60' 1.748
1/8 7.844
ET 12.269
MPH 111.4

Any advice on bringing the 60' down? By the way, all my runs were in the 1.7 range, even when I didn't spin the tires hard.