2nd digit: Series number:
S = Base Firebird
T = Esprit
U = Formula
V = Trans Am (72 - 74)
W = Trans Am (75 - 80)
X = 10th Anniversary Trans Am (79)
X = Turbo Indy Trans Am (80)

3rd and 4th digits: Body type number:
87 = Sport Coupe

5th digit: Engine code:
A = 231 c.i.d, 2-bbl V6 (1978 - 80)
C = 231 c.i.d, 2-bbl V6 (1977)
D = 250 c.i.d, 1-bbl V6 (1972 - 76)
G = 305 c.i.d, 2-bbl V8 (1979)
H = 350 c.i.d, 4-bbl V8 (1975)
H = 305 c.i.d, 4-bbl V8 (1980)
J = 350 c.i.d, 4-bbl V8 (1976)
K = 403 c.i.d, 4-bbl V8 (1977 - 79)
L = 350 c.i.d, 4-bbl V8 (1978)
M = 350 c.i.d, 2-bbl V8 (single exhaust) (1972 - 76)
N = 350 c.i.d, 2-bbl V8 (dual exhaust) (1972 - 74)
R = 400 c.i.d, 2-bbl V8 (single exhaust) (1972 -74)
P = 400 c.i.d, 2-bbl V8 (dual exhaust) (1973 -74)
P = 350 c.i.d, 4-bbl V8 (1977)
R = 350 c.i.d, 4-bbl V8 (1977
S = 400 c.i.d, 4-bbl V8 (1975 - 76)
S = 265 c.i.d, 2-bbl V8 (1980)
T = 400 c.i.d, 4-bbl V8 (dual exhaust) (1972 -74)
T = 301 c.i.d, TC 4-bbl V8 (turbo) (1980)
U = 305 c.i.d, 2-bbl V8 (1978)
W = 455 c.i.d, 4-bbl V8 (1975 -76)
W = 301 c.i.d, 4-bbl V8 (1979 -80)
X = 455 c.i.d, 4-bbl V8 (Super Duty) (1973 -74)
X = 455 c.i.d, 4-bbl V8 (1973 - 74)
Y = 301 c.i.d, 2 -bbl V8 (1977, 1979)
Y = 301 c.i.d, 4-bbl V8 (T/A 4.9) (1980)
Z = 400 c.i.d, 4-bbl V8 (1977 - 79)

6th digit: Last digit of model year:
2 = 1972
3 = 1973
4 = 1974
5 = 1975
6 = 1976
7 = 1977
8 = 1978
9 = 1979
A = 1980

7th digit: Assembly plant location:
L = Van Nuys, California
N = Norwood, Ohio

8th through 13th digits: Sequential production
number starting with 500001 for 1972 models
and 100001 for 1973-80 models

2nd digit: G = General Motors

3rd digit: Division: 2 = Pontiac

4th digit: Restraint system:
A = non-passive
B = automatic belts
C = inflatable restraint

5th digit: Series:
S = Base Firebird
T = Esprit
V = Formula
W = Trans Am
X = Trans Am Special Edition
Y = NASCAR Turbo Trans Am pace Car

6th and 7th digits: Body style:
87 = Sport Coupe

8th digit: Engine:
A = 231 c.i.d, 110hp 2-bbl V6
H = 305 c.i.d, 145hp 4-bbl V8
S = 265 c.i.d, 120hp 2-bbl V8
T = 301 c.i.d, 200hp TC 4-bbl V8 (Turbo)
W = 301 c.i.d, 135hp (or 150hp T/A 4.9) 4-bbl V8
L = 350 c.i.d, 175hp 4-bbl V8

9th digit: Check digit

10th digit: Year: B = 1981

11th digit: Assembly plant:
L = Van Nuys, California
N = Norwood, Ohio

12th through 17th digits: Sequential production
number starting with 100001