Im runing 13.9 with m/t sport pros, i have to leave the line at a low rpm, id have to say those 1-5/8 headers are hurting you, possibly, my car is light but look at my mods, still stock headers too.
get the megabites, and some subframe connectors would really help, i love my sfc's, my car leaves harder/straighter with them.
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Police package 5spd 90 Lx, Stock original motor, 3.27grs, BM fan, fms 10.5 clutch, D&D quadrant, and adjuster, ADS chip, 180 stat, mac cai, mac h-pipe, mac subframe connectors, ASP crank pulley, ripper shifter, 26x10.5 M/T sport pros welds. 246 hp according to analyzer 
Race weight: 3,120
E.t-13.57 with 26x10.50's e.t. streets. 1.88 60'
mph- 99.92 mph
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