[Shotimes] Three letter Spring Codes versus Single Letter VIN tag spring codes

[Fred George]

Anyone know how to correlate the single-letter VIN tag spring codes with 
the three-letter spring codes that have been previously published by our 
user group experts?

My 89 GEN 1 SHO has JJJJ for each spring at each corner, left front / 
right front / left rear/ right rear. Now how do I match up those 
single-letter codes with the three letter codes. And, just as 
importantly, which single-letter code matches up with the heaviest-duty, 
"LAT" 596 lb rating / 130 lb/inch rear springs?

Thanks,

Fred