OK..the newer V6 stangs run mid 15's with stick and low 16's auto so I doubt you will beat them stock unless the guy in the 5spd stang can't drive because an auto is not always the slowest...hard to miss a shift with one. But from light to light or 1/8th mile it can be different. My friend had a 99 V6 Camaro with an auto and ran 16.0 stock so they too are not bad. He now has a 2000SS Camaro that he ran 13.4@105 with traction probs so good luck there, I know it can run 12.9's eay with a different driver..TransAm's are the same and sometimes faster. Unless you raced a 80's TA it isn't going to happen. I beat a 96 Eclipse RS the other day with my 89 Probe that runs 16.4 but I would not claim that I can kill any Eclpise. Too many variables to consider when racing and it all depends on the driver. A 13 sec car with a 14 sec driver is gonna run 14's if you see what I'm saying.

'00 Harley-Davidson F150
'88 Mustang GT
'93 Mustang LX 5.0
'00 Focus (beater)