3=OLDSMOBILE 31 & 32 =F85 MODELS 35=CUTLAS 6 CYL 36=CUTLAS 8 CYL EXC.SUPREME & SKYROOF 42= CUTLAS SUPREME 44 = 4-4-2 48 =SKYROOF STA WGN . BODY TYPES 35 S.W.EXCEPT SKYROOF 39 = 4DR HARDTOP 55 = SKYROOF SW 2 SEAT 65 = 3 SEAT SKYROOF S W 67 = CONVERTIBLE 69 = 4DR SEDAN 77 = 2DR SEDAN 87 = 2DR HT THE 8 IS THE MODEL YEAR . THE LETTER IS ASSEMBLY PLANT . REST IS VIN NUMBER. IF YOU NEED MORE HELP GIVE # UPTO ASSEMBLY PLANT AND I WILLBREAK IT DOWN FOR YOU. ENGINES HAD A TAPE WITH CODES ON THE OIL FILLER TUBES ,[ USUALLY MISSSING ] UNLESS IT IS A 6 CYL.

people do it all the time - just look at other posts on oldride - but you should only do what you feel comfortable doing.