From 1962 through 1972, the Chevy II and Nova evolved from a lightweight compact into one of Chevrolet’s most versatile and collectible muscle platforms. Whether you’re decoding a rare L79 327 Nova SS, restoring a six-cylinder grocery-getter, or verifying a big-block 396 car, understanding GM RPO (Regular Production Option) codes is the key to unlocking your car’s original identity. These factory-issued three-character codes reveal how every Nova was built from the engine, to the transmission, and axle ratios to suspension, trim, and appearance packages.
Nova Model Year Breakdown
1962–1965 Chevy II/Nova (1st gen): Compact, lightweight cars with the 153ci four and Turbo-Thrift sixes (194/230) dominating. The SS appeared as an option package in 1963 (RPO Z03), mostly cosmetic that year.
1966–1967 (1st-gen facelift): Performance turned up. The 327-350 hp L79 made the ’66 Nova SS a legend; other 327 options included L30.
1968–1972 Nova (3rd gen for Nova nameplate): Broader option spread, true SS performance packages now bundled under Z26 (Nova SS) with small-block 350s and big-block 396s offered in select years. Popular chassis and axle RPOs become common (F41, G80).
Nova Engine RPO Codes
| RPO | Engine & Notes | Typical Years/Use |
|---|---|---|
| 153 (engine family) | 153ci inline-4 “Super/Hi-Thrift” (base Chevy II) | ’62–’65 base fitments (verify by year) Curbside Classic |
| L22 / L14 (by year)* | 194ci Turbo-Thrift inline-6 (120 hp gross early) | ’62–’67 Chevy II/Nova (verify code label per year) Wikipedia |
| L33 / L26 (by year)* | 230ci Turbo-Thrift inline-6 | Mid-’60s; availability varies by year/trim Wikipedia |
| L30 | 327ci V8 (commonly 275 hp) | ’65–’67 Nova (and other Chevy lines) Curbside Classic |
| L79 | 327ci/350 hp V8 (high-perf) | 1966 Nova SS highlight; rare and prized |
| L48 | 350ci/300 hp small-block | Common Nova performance V8 from ’68-’72; often tied to SS content depending on year Steve’s Nova Site |
| L34 / L78 | 396ci big-block V8s (350/375 hp) | ’68–’70 Nova SS (availability varies by year) |
*GM reused base-engine identifiers across lines; consult your year-specific Heritage kit to confirm the exact three-character RPO attached to the 194/230/250 for your car.
Nova Transmission RPO Codes
| RPO | Transmission | Notes |
|---|---|---|
| M20 / M21 / M22 | 4-spd manuals (wide/close/“Rock Crusher”) | Performance Novas; year/engine dependent |
| M15 / MM4 | 3- or 4-spd manual (earlier base transmissions) | Early Chevy II/Nova manual options |
| M35 (Powerglide) | 2-spd automatic | Extremely common through ’67 and still seen later |
| M38 (TH350) | 3-spd Turbo-Hydramatic 350 | Arrives with late-’60s small-blocks |
| M40 (TH400) | 3-spd Turbo-Hydramatic 400 | Big-block or heavy-duty applications |
Confirm by year/engine in the Heritage kit; NovaResource master lists also track many of these.
Nova Axles and Differential RPO Codes
| RPO | Description |
|---|---|
| G80 | Limited-slip differential (Positraction) |
| GM1/GM3/GM8 | Tall/economy ratios (e.g., 2.56) depending on year |
| GU2/ GU4/ GU5/ GU6 | 2.73 / 3.08 / 3.23 / 3.42 ratios (application-dependent) |
| GT4 / GT5 | 3.73 / 4.10 ratios (rare on street Novas; verify) |
Axle ratio codes and meanings are consistent across GM lines but vary by which ratios were offered in a given Nova year; cross-check your SPID/build sheet.
Nova Chassis and Suspension RPO Codes
| RPO | Package |
|---|---|
| F40 | Heavy-duty suspension (earlier usage varies by line) |
| F41 | Special/firm ride & handling suspension (popular on performance Novas) |
| N10 | Dual exhaust (often tied to V8 performance packages) |
| N40 | Power steering |
These codes are common across Chevrolets; Nova availability depends on trim/year.
Nova Performance Package RPO Codes
| RPO | Package | Years/Notes |
|---|---|---|
| Z03 | Super Sport package (early) | 1963 Chevy II/Nova SS option on 400-series (largely appearance that year) |
| Z26 | Nova SS package (late) | 1968+ Nova SS; bundled performance chassis, styling, and V8 content by year. (Earlier/later usage of Z26 evolves; verify by year.) Nova Resource+1 |
| ZJ7 | Rally wheels (14×6, style varies by year) | Common on SS/“Rally” trims; confirm width/finish per year |
Nova Interior RPO Codes
| RPO | Description |
|---|
| U14 | Special instrumentation/gauges (factory gauge package) |
| D55 | Front console (with floor shift) |
| A01 | Tinted glass (all windows) |
| C60 | Air conditioning |
| K30/K34 | Cruise control variants (availability varies by year) |
| U63 / U69 | AM radio / AM-FM radio |
| AK1 | Deluxe belts/harnesses |
Factory gauge/console bundles show up heavily on ’68–’72 cars; original-style console gauge assemblies are still sold specifically for 1968–1972/74 Nova restorations, which mirrors how often U14/console packages appeared on performance trims.
Why RPO Codes Don't Tell The Whole Story
GM reused many codes across divisions and years; some codes changed meaning slightly or were package-dependent. Plants sometimes stamped option info differently (e.g., early SS identification on cowl tags), and some years don’t encode everything on the VIN. For Nova SS identification and year-specific package details, combine the SPID/build sheet, the Heritage kit, and a trusted Nova-specific reference.
Reference Links
GM Heritage Center — Vehicle Information Kits (free PDFs; option charts, specs by year). General Motors
NovaResource — Nova SS history and RPO tables (Z03, Z26, production counts for many RPOs starting in ’68). Nova Resource+2Nova Resource+2
Engine & year context — L79/L30 period sources and reviews to understand 1966 SS significance. Ground Up – SS396+1
General RPO quick lists — cross-line code dictionaries (useful for F41, G80, GU/GT ratios, etc.) with the caveat to verify Nova applicability per year. Chevy Talk
Do you need help decoding the RPO codes on your Chevy II or Nova? Give our friendly experts a call at (203) 235-1200! For all your Nova parts, hop on SS396.com for a full line up.
