took car to the track why so slow

[nascartech]

ok so i whent to the track to see my time and i could only run a 15.6 my mods are 3.2 ssic headers stock tune getting 8 psi boost and lots of kr 5 deg but even with 5 deg kr i should still be 14.8 i also had no traction best 60 ft of 2.3 left at 2300 rpm and had to feather it alot im thinking put my 3.5 back on and tune it