they were all coded to the body
B=Impala. etc
A=Chevelle
F=Camaro
regardless of WHAT it originally came in you can make them FIT in other applications
lots of great info here:
http://www.wonderbarman.com/codes.html
Specifically:
Let's say the "Service Model Number" is:
02GFM1
1970 Pontiac Grand Prix AM/FM~Stereo
The first digit is the model year of the radio 0=1970. So 8=1968, 9=1969, 0=1970, 1=1971, 2=1972 3=1973, 4=1974, 5=1975 after that i have no literature for info. BUT i do believe that they rest for the next decade so a 1 could be a 71 or 81 model year
The second digit is the car line:
1 = Chevrolet
2 = Pontiac
3 = Oldsmobile
4 = Buick
5 = Cadillac
6 = GMC
The third element is a letter which corresponds to the fisher body style the radio goes in:
A - Midsized: Tempest, Chevelle, Camaro, ChevyII, Acadian, Skylark/GS, [GTO not listed by Delco but is a Tempest or LeMans, GT37, T-37 Pontiac model radio]
B - Fullsized model: Bonneville etc.
C - More than full sized: Cadillac Fleetwood.
D - Rear control: Cadillac 75
E - Toronado, Riviera
F - Pony car: Firebird etc.
G - Grand Prix etc.
H - Subcompact: Sunbird etc.
L - Opel
T - Truck
TTC - GMC truck tilt cab
V - Corvette, sometimes the V looks like a Y ?
X - Compact: Nova etc.
Z - Corvair etc.
The next two letters indicate the type of radio:
PB - Push Button AM
FP - AM/FM mono
FM - AM/FM~Stereo
K - Fader Control
MP - FM Multiplex adapter (second part of a two-piece radio)
T - Stereo Tape Player (8-track)
RV - Reverberation Amplifier
FW - AM/FM/Weather band
MW - AM/FM~Stereo/Weather band