Here's a list of few more Z-Codes I've saved from somewhere online...
Please note some are included twice and some are missing from this list also keep in mind some could even be wrong too..
~ Pete
Z10 ('69 only) Indy pace car accents Coupe
Z11 ('69 only) Indy pace car accents Convert.
Z21 Style trim group
Z22 Rally Sport
Z23 Special interior package
Z27 SS equipment
Z28 Special performance package
Z87 Custom Interior group
ZO1 Comfort and Convenience Group, '64-65.
ZO2 Pushbutton Radio and extra speaker, '64.
ZO4 Heavy Duty Chassis, '64-65.
ZO8 Body Molding/Trim
ZJ7 Ralley Wheels
ZJ9 Auxiliary lighting group
ZJ6 Special Sport Sedan, '68+
ZJ7 Steering Wheel Deluxe Trim
ZJ9 Auxiliary Lighting Group
ZK3 Deluxe Seat Belts, and Front Shoulder Harness, '68+
ZK5 Concours Sedan, '68
ZK6, 7 Concours Sport Coupe, '68
ZK8 - Refers toTire Pressure Label, '70
ZKQ - tire pressure sticker
ZL2 Special Hood, Cowl Induction, '70+
ZL3 SS 396 CONVER--
ZO9 Performance Rear Axle, '70+
Z10 Pace car coupe
Z11 Indy pace car convertible
ZP2 *Trim & color override. This was for cars that had an exterior/interior color or trim combination that was not normally available. This code is listed on the build sheet for a '71 GMC Sprint that was "Classic Copper" with a "Dark Saddle" interior - a color combination not normally available.
ZR3 Refers to: = Off road package 454(LS7 & LT2) 69*
Z02 refers to: **SPEC PAINT** (from 72 tag)
ZP5 *Appearance guard group.
ZW4 *Std Trans 3spd (70)
Z13 Comfort and Convenience Group, second style, '64-65.
Z14* Refers to: = A/C BODY CONV (info from 72 Chevelle)
Z15 SS equipment. (454 in '70)
Z16 Special Sport Coupe - 65 Chevelle
Z19 Convenience Group, '66.
Z20 Monte Carlo SS 454
Z25 Super Sport Option, '69+
Z29 Vinyl Stripe
Z49 Canadian Base Equipment
Z57 Vinyl Coated Trim
Z83 Road Hazard Package, '66.
Z95 Regular Fuel Engine Equipment