My guess is a stock GT or a slightly modified one with a bad 60'

I had an identical time (ok, so it was a 16.815) the only time I took Ol Blue to a 1/4 strip (had always been to 1/8 strips prior). I had an excellent 60' on my street tires which was a 2.25, and right after the 60' the fuel pump choked. Had to baby her down the track, running less than 1/2 throttle and letting off more and more due to the pump heating up more and more. I totally let off with about 300' to go and when I hit the traps I had been on the brakes for about 50'.

New pump and tank and now this year with a little more modding I hope to have Ol Blue running 15 flat (have my fingers crossed), but in strip down mode. 15.3'* in street trim. No slicks.