Here you go, a VIN decoder for 1987 through 1996, I think it is. The typos are some one else's. I just copied this long ago.
This, of course, assumes that no one has swapped engines. A more thorough look at the engine itself is a more reliable method.
1987 to 1996
Positions 1, 2 & 3-Country Code:
1FT Ford Motor Company USA
2FT Ford Motor Company Canada
Position 4-GVW Class Code:
C 4001 to 5000 pounds F150
D 5001 to 6000 pounds F150
E 6001 to 7000 pounds F150 & F250
F 7001 to 8000 pounds F250
G 8001 to 8500 pounds F250
H 8501 to 9000 pounds F250 HD & F350
J 9001 to 10000 pounds F350
Positions 5, 6 & 7-Series Code:
F15 F150 2 Wheel Drive Reg Cab
X15 F150 2 Wheel Drive Ext Cab
F14 F150 4 Wheel Drive Reg Cab
X14 F150 4 Wheel Drive Ext Cab
F25 F250 2 Wheel Drive Reg Cab
X25 F250 2 Wheel Drive Ext Cab
F26 F250 4 Wheel Drive Reg Cab
X26 F250 4 Wheel Drive Ext Cab
Position 8-Engine Code:
Y 6 cy 4.9 Gas EFI 87 to 93
Y 6 cy 4.9 Gas MFI 94 to 96
N 8 cy 5.0 Gas EFI 87 to 93
N 8 cy 5.0 Gas MFI 94 to 96
H 8 cy 5.8 Gas 4BBL 87
H 8 cy 5.8 Gas EFI 88 to 93
R 8 cy 5.8 Gas F150 Lt EFI 93
H 8 cy 5.8 Gas MFI 94 to 96
R 8 cy 5.8 Gas F150 Lt MFI 94 to 95
1 8 cy 6.9 Diesel IDI 87
M 8 cy 7.3 Diesel IDI 88 to 94
F 8 cy 7.3 Turbo-Diesel TPS 94 to 96
K 8 cy 7.3 Turbo-Diesel TPS 94
L 8 cy 7.5 Gas 4BBL 87
G 8 cy 7.5 Gas EFI 88 to 93
G 8 cy 7.5 Gas MFI 94 to 96
Position 9-Model Year Code:
H-87, J-88, K-89, L-90, M-91
N-92, P-93, R-94, S-95, T-96
Position 10-Assembly Plant Code:
C-Oakville, Ontario Canada
H-Lorain, OH / N-Norfolk, VA
K-Kansas, MO / P-St. Paul, MN
L-Wayne, MI / U-Louisville, KY
Remaining Numbers-Sequence of Assembly:
EXPANDED:::
F14 - F150, Regular Cab, 4x4
x14 - F150, SuperCab, 4x4
F15 - F140, Regular Cab, 4x2
X15 - F150, SuperCab, 4x2
F25 - F250, Regular Cab, 4x2
X25 - F250, SuperCab, 4x2
F26 - F250, RegularCab, 4x4
X26 - F250, SuperCab, 4x4
F35 - F350, Regular Cab, 4x2
X35 - F350, SuperCab, 4x2
W36 - F350, Crew Cab, 4x2
F37 - F350, Regular Cab (Chassis Cab), 4x2
F36 - F350, Regular Cab, 4x4
W36 - F350, Crew Cab, 4x4
F38 - F350, Regular Cab (Chassis Cab), 4x4
F47 - F-Super Duty, Regular Cab (Chassis Cab), 4x2
F53 - F-Super Duty, RV Stripped Chassis, 4x2
F59 - F-Super Duty, Commercial Basic Stripped Chassis, 4x2
The ninth VIN position is a government assigned, computer-generated check digit.
The tenth VIN position is the Vehicle Model Year.
K - 1989
L - 1990
M - 1991
N - 1992
P - 1993
R - 1994
S - 1995
T - 1996
The elenth VIN position is the Assembly Plant Code.
C - Ontario Truck: Oakville, Ontario
E - Kentucky Truck: Jefferson, Kentucky
H - Lorain: Lorain, Ohio
K - Kansas City: Claymoco, Missouri
L - Michigan Truck: Wayne, Michigan
N - Norfolk: Norfolk, Virginia
P - Twin Cities: St. Paul, Minnesota
U - Louisville: Louisville, Kentucky
V - Kentuck Truck: Jefferson, Kentucky