Temp/Humidity can add .75 to the "best" time.
Assuming in all the runs you left it in "D" with the "OD" off it could be a number of factors including a slipping trans.
Frequently it is more than just one factor.
Good Luck in figuring it out.
With a Tune and 4:10;
60 330 Eight MPH 1,000 Quarter MPH
2.183 6.102 9.27 78.26 12.007 14.331 97.08
2.168 6.062 9.214 78.53 11.95 14.274 97.05
2.166 6.062 9.218 78.44 11.956 14.286 96.79
2.194 6.098 9.261 78.34 11.987 14.305 97.3
1/4 Mile Time 11.542 @ 121.19 MPH
195,000 Miles & 275+ Runs Down the 1,320’
541.57 RWHP & 476.64 RWTQ on DynoJet
Tuned by Aric at Injected Engineering
Vortech Super Charger V-2 “T” Trim, 19 PSI
8 Rib Belt, Innovators West 10% Overdrive Dampner
Air to Air Intercooler, Mini-race Bypass
Ford Cobra Remanufactured Long Block
Snow Performance Water-Methanol Injection
Kooks Headers & X Pipe
GT MAF, 60lb injectors, Dash 8, Aero Rails, Twin Ford GT Pumps,
Kinsler Fuel Filter, Kenne Bell Boost-A-Pump
Monroe Sensatrac, Metco Control Arms, Addco Rear Sway Bar
31 Ford Spline Axles & Detroit Truetrac, 4:10 Ford Racing Gears
Dynotech MMC Driveshaft
A-1 Performance Trans, Forced Tailshaft Lube, Carbon Clutches
3,500 RPM Stall Precision Industries Torque Converter
B&M Deep Finned Trans Pan
AeroForce Scan Gauges , Auto Meter Oil, Fuel & Boost Gauges
Kenny Brown Dead Pedal, 35% Tint, Silver Star Head Lights
AutoPage Alarm RS-727LCD, Boston Acoustic NX87