This is from my Haynes Repair Manual for '94-'03 'Stangs
Counting from the left the 8th (eighth) digit is the engine code:
4 = 3.8L V6
W = 4.6L SOHC V8
V = 4.6L DOHC V8
T = 5.0L H.O. V8
D = 5.0L Cobra V8
The 10th (Tenth) digit (from left) is the year of the car:
R = 1994
S = 1995
T = 1996
V = 1997
W = 1998
X = 1999
Y = 2000
1 = 2001
2 = 2002
3 = 2003
And that's all it says.