First digit: car make

B = Barracuda J = Challenger L = Dart R = Belvedere / Satellite V = Valiant / Duster W = Coronet / 1971-74 Charger X = 1966-70 Charger 

Second digit: series number

L = Belvedere(68-70), Charger coupe(71-74), Coronet(68-74), Dart(68-74), Dart swinger(68-70), Dart swinger special(71-74), Dart sport(73-74), Demon(71-72), Duster(70-74), Satellite coupe(71-74), Valiant(68-74)

M = Coronet Superbee(68-70), Dart swinger 340(69-70), Demon 340(71-72), Dart sport 340(1973), Dart sport 360(1974), Road Runner(68-74), Road Runner Superbird(1970), Road Runner GTX(72-74),

H = Barracuda(68-69), Barracuda 'cuda(1969), Barracuda(1970-74), Challenger(1970-74), Challenger T/A(1970), Charger(1970), Charger hardtop(71-74), Coronet Custom(71-74), Coronet 440(68-70), Dart 270(1968), Dart custom(69-70), Dart swinger(71-74), Satellite(68-70), Satellite Sebring(71-74), Satellite Custom(71-74), Scamp(71-74), Valiant Signet(68-69)

P = Barracuda Gran Coupe(70-71), Charger(68-69), Charger 500(70-71), Charger SE(71-74), Coronet 500(68-69), Coronet Brougham(1971), Crestwood(71-74), Dart GT(68-69), Dart SE(1974), Regent(68-69), Satellite Sport(68-70), Satellite Sebring Plus(71-74), Satellite Brougham(1971), Valiant Brougham(1974)

S = Barracuda 'cuda(70-74), Barracuda 'cuda AAR(1970), Challenger R/T(70-71), Challenger Rallye R/T(1972), Charger R/T(68-71), Charger 500(early 1969), Coronet R/T(68-70), Dart GTS(68-69), Dart GSS(1968), Duster 340(70-73), Duster 360(1974), GTX(68-71)

X = Charger 500(late 1969), Charger Daytona(1969)

O = Barracuda Super Stock(1968) and Dart Super Stock(1968)

K = Belvedere Police(68-70), Coronet Police(68-74), Satellite Police(71-74)

N = Coronet New York Taxi(1970-71)

G = Coronet New York Taxi(1972-74)

T = Belvedere Taxi(68-70), Coronet Taxi(68-74), Satellite Taxi(71-74) 

Third and Fourth digit: body style

21 = 2-door sedan 23 = 2-door hardtop 27 = 2-door convertible 29 = 2-door sports hardtop 41 = 4-door sedan 45 = 4-door station wagon(6 passenger) 46 = 4-door station wagon(9 passenger) 

Fifth digit: engine

A = 170ci/115hp 1-bbl L6 (1968-69)

B = 225ci/145hp 1-bbl L6 (1968-69)

B = 198ci/125hp (1970-71), 100hp (1972) or 95hp (1973-74) all with 1-bbl L6

C = special order L6 (1968-69)

C = 225ci/145hp (1970-71), 110hp (1972) or 105hp (1973-74) all with 1-bbl L6

D = 273ci/190hp 2-bbl V8 (1968-69)

E = special order L6 (1970-74)

F = 318ci/230hp 2-bbl V8 (1968-69)

G = 383ci/290hp 2-bbl V8 (1968-69)

G = 318ci/230hp (1970-71), 150hp (1972-74), 155hp (1972) or 170hp (1973-74 Road Runner) all with 2-bbl V8

H = 383ci/330hp or 335hp 4-bbl V8 (1968-69)

H = 340ci/275hp (1970-71) or 240hp (1972-73) both with 4-bbl V8

J = 426ci/425hp 2 x 4-bbl V8 HEMI (1968-69)

J = 340ci/290hp 3 x 2-bbl V8 (1970) (AAR and T/A)

L = 440ci/375hp 4-bbl V8 (1968-69)

L = 383ci/290hp (1970) or 275hp (1971) both with 2-bbl V8

L = 360ci/200hp or 245hp 4-bbl V8 (1974)

M = special order V8 (1968-69)

M = 440ci/390hp 3 x 2-bbl V8 (1969)

M = 400ci/190hp (1972), 175hp (1973) or 185hp (1973) all with 2-bbl V8

N = 383ci/330hp (1970), 335hp (1970) or 300hp (1971) all with 4-bbl V8

N = 400ci/205hp 4-bbl V8 (1974)

P = 340ci/275hp 4-bbl V8 (1968-69)

P = 400ci/255hp (1972), 260hp (1973) or 250hp (1974) all with 4-bbl V8

R = 426ci/425hp 2 x 4-bbl V8 HEMI (1970-71)

U = 440ci/375hp (1970), 370hp (1971), 290hp (1972), 280hp (1972-73) or 275hp (1974) all with 4-bbl V8

V = 440ci/385hp (1971) or 330hp (1972) 3 x 2-bbl V8

Z = special order V8 (1970-74) 

Sixth digit: model year

8 = 1968 9 = 1969 0 = 1970 1 = 1971 2 = 1972 3 = 1973 4 = 1974 

Seventh Digit: assembly plant

A = Lynch Road, Detroit, MI B = Dodge Main, Hamtramck, MI C = Jefferson Avenue, Detroit, MI D = Belvidere, IL E = Los Angeles, CA F = Newark, NJ G = ST. Louis, MO H = New Stanton, PA P = Export R = Windsor, ONT. Canada 

Eighth through thirteenth digits seq. production number:    Sequential numbering system starting with 100001