Line 5 Build Codes. Build codes run from line 3, 4 and 5. Most of the numbers are the last few digits of the "factory production" part numbers. TORSION BAR LT RT: The last three digits of the part number for the Torsion Bars Left and Right. LT 779 = 1857779 Left HD 41x.090 B-body 781 = 1857781 Left HD 41x.092 B-body 440/426 RT 778 = 1857778 Right HD 41x.090 B-body 780 = 1857780 Right HD 41x.092 B-body 440/426 REAR SPRINGS LT RT: The last three digits of the part number for the Rear Springs Left and Right. LT 794 = 2539794 Left B-body 6 leafs RT 964 = 2539964 Right B-body 5 full + 2 ˝ leafs CLUTCH/BRAKE PEDAL: The two digit code for the Clutch and Brake Pedal. For 1971 the first box is for the BRAKE PEDAL, the second box is for the CLUTCH PEDAL. BRAKE 53 = 4-spd - manual brakes 57 = Automatic - manual brakes 63 = 4-spd - power brakes 67 = Automatic - power brakes 68 = Automatic - power brakes w/speed control CLUTCH 00 = Automatic - no clutch standard pedal 01 = Automatic - no clutch pedal dress up 20 = 4-spd - standard clutch pedal 21 = 4-spd - pedal dress up LABELS: Two separate boxes. The first box is the last two digits of the part number for the Vehicle Lable VEC. The second box is the last two digits of the part number for the tire pressure decal lable TIRE. VEC 32 = 3577732 340 CID 4bbl 72 = 3614872 383 CID 4bbl Manual Trans 73 = 3614873 383 CID 4bbl Auto Trans 75 = 3614875 440 CID 4bbl Manual Trans 76 = 3614876 440 CID 4bbl Auto Trans 77 = 3614877 440 CID 6bbl 78 = 3614878 426 CID 4bbl Manual Trans 79 = 3614879 426 CID 4bbl Auto Trans TIRE 63 = 3402163 B-Body G70x14 36 = 3402336 B-Body F70x14 EXHAUST: The last two digits of the factory assembly line part number for the Exhaust system. LT 00 = UNKNOWN PART # Dual exhaust RT 01 = UNKNOWN PART # Dual exhaust TAIL PIPE: The last two digits of the factory assembly line part number for the for the Tail Pipes. LT 03 = 3466103 Chrome RT 02 = 3466102 Chrome CAR HEIGHT: This code is for the car ride height. BM5 BM3 BP5 BP3 MAS CYL: The last two digits of the factory assembly line part number. 31 = B-body 440 CID drums front/rear 42 = B-body 440 CID w/power drum brakes 43 = B-body 426 CID 2x4bbl w/power drum brakes 45 = B-Body 440 CID w/power disc brakes 46 = B-body 426 CID 2x4bbl w/power disc brakes FRONT BRAKE LT RT: The last two digits of the factory assembly line part number. LT 11 = B-body w/11" Drum 67 = B-body w/disc brakes RT 10 = B-body w/11" Drum 66 = B-body w/disc brakes