Baltimore, Maryland ~ Section 4 ~ 43 through 59

Box 43: TRIM
This box contains a 3-letter code corresponding to the interior trim color, seat type, and material. See interior trim codes for examples.

Box 44: COLOR
This box contains 4 sections.
LW ~ a 2-digit number corresponding to the lower body paint color. If a special order paint this section will show SPCL.
UP ~ a 2-digit number corresponding to the upper body paint color or a single letter pertaining to a vinyl or convertible top color. If a special order paint (and no vinyl or convertible top) this section will typically show a single hyphen ( - ).
ST ~ a single letter corresponding to the factory applied color for RPO D88 stripes if ordered (B for black or W for white). If no stripes ordered this section will have 1 hyphen ( - ).
W ~ all SS-optioned Chevelles with standard SS wheels will have 2 hyphens ( -- ) in this section.
See exterior paint codes for examples of paint numbers and vinyl/convertible top letters.

Box 45: WHEELS
YA ~ through at least 11-20
AO ~ from at least 11-25

Box 46: RADIATOR
This box contains a 4-character code, generally a 2-digit number, 2 spaces, followed by 2 letters or two hyphens ( -- ), 2 spaces, followed by 2 letters. While there are consistencies in the codes for various combinations of engine, transmission, and air conditioning, there are also exceptions and for some engine/transmission combinations there are more than one radiator used.
-- PA ~ LS6 with mM22 with 4.10:1 ⁽¹⁾
-- PD ~ LS6 with M40 with 4.10:1 ⁽²⁾
53 PA ~ L34 with M21 and C60; LS5 with M22 and C60; LS6 with M22 & with 4.10:1 ⁽¹⁾
53 PD ~ L34 with M40 and C60; L34 El Camino with M40; LS5 with M40; LS6 with M40 and 4.10:1
65 BE ~ L34 with manual transmission without air conditioning
65 BK ~ L34 with M40 without air conditioning
65 BM ~ LS6 with M40 with 3.31:1 ⁽²⁾
65 BO ~ L78 with manual transmission
65 BQ ~ LS5 & LS6 with M22 transmission with 3.31:1
65 BR ~ LS5 & LS6 with M40 transmission with 3.31:1

(1) ~ One exception is a 12-19 LS6 with 3.31:1
(2) ~ Only two examples, early January

Box 47: RADIATOR UPR HOSE
This box contains a 2-letter code for the upper radiator hose.
SV - Engines with or without air conditioning and/or 4.10:1
KY - Engines without air conditioning and 3.31:1 with one exception found to date with air conditioning
Note: LS6 engines have been found with both SV and KY regardless of rear end gear ratio

Example "SV" hose on LS6 w/4.10:1 ratio rear end gear

Example "SV" hose on L34 w/air conditioning and 3.31:1 ratio rear end gear

Example of "KY" hose on LS6 w/3.31:1 ratio rear end gear

Box 48: RADIATOR LWR HOSE
This box contains a 2-letter code for the lower hose.
SZ ~ all

Box 49: BATT
This box contains the AC-Delco number for the particular battery used in the car.
R59 ~ L34 without RPO T60 heavy duty battery option
R79W ~ L34, LS5, & LS6 with RPO T60

Box 50: BATTERY POS CABLE
This box contains a 2-letter code for the positive battery cable.
NE ~ R59 battery
NG ~ R79W battery

Box 51: BATTERY NEG CABLE
This box contains a 2-letter code for the negative battery cable.
PB ~ R59 battery from at least 01-12
FV ~ R79W battery through at least 01-16
PE ~ R79W battery from at least 01-21
YG ~ R59 through at least 12-30

Box 52: A/C COMPRESSOR
This box contains a 3-digit code 738 for Chevelles equipped with air conditioning; those not optioned for air conditioning show 3 hyphens ( --- ).

Box 53: FRT. END HARNESS
This box contains a 3- or 4-character code.
VM -- ~ all engines without U16 gauges
VM H ~ all engines without U16 gauges (no discernable difference in other options)
XM -- ~ all engines with U16 gauges
XM H ~ all engines with U16 gauges (no discernable difference in other options)

Box 54: ENGINE HARNESS
This box contains a 2-letter code and is dependent on transmission type.
YC ~ manual transmission
YD ~ automatic transmission

Box 55: AIR CLEANER
This box contains a 2-letter code.
CO ~ open element LS6 (after at least 01-23)
DG ~ All open element with cowl induction
SS ~ All open element without cowl induction (LS6 only prior to at least 01-05)

Box 56: HYDRO PIERCE
This box contains a 2-letter code.
YF ~ All SS El Camino
YM ~ All sport coupe & convertible

Box 57: ANTENNA
This box has been found to contain several different codes but no rhyme or reason based on radio type or no radio at all yet all have RPO U76 W/S ANTENNA in box 107.
--- ~ - (3 hyphens, a space, a 4th hyphen) found with UM1, U63, U69, & U79 ~ all 3 body styles
780 ~ found only to at least 12-01
C-6 K ~ found on 3 sport coupes with UM1 (2) & U63 (1)
C-6 L ~ found after 12-08 on sport coupe & convertible with U63, U69, U79, UM1, & UM2
C-6 M ~ found after 12-30 on sport coupe & convertible with U63, U69, UM1, & UM2
C-6 P ~ found on one convertible with UM2 dated 02-23
C-6 K ~ found on one convertible with U63 dated 02-25

Box 58: HTR HSE INLET
This box contains one of two codes and is dependent on air conditioning being ordered.
926-- ~ without air conditioning
32-35 ~ with air conditioning

Box 59: HTR HSE OUTLET
This box contains one of two 3-digit numbers dependent on air conditioning being ordered.
929 ~ without air conditioning
936 ~ with air conditioning