Mopar VIN Decoder: The Year Every Chart Forgets

Type mopar vin decoder into Google and you get a wall of free lookup tools, a factory page written for somebody who just bought a new Ram, and a handful of enthusiast charts that all print the same table. Hand most of them a real 1970 Plymouth VIN and they will tell you something flatly untrue, because Chrysler reassigned the engine letters for 1970 and almost none of those charts carries a model year.

This is the catch our own muscle car decoder was built around, and it is not subtle. It is sitting on page one right now, inside the worked example one of those guides uses to teach the system.

What a Mopar VIN Decoder Can Actually Read

Chrysler ran a 13 character VIN on its passenger cars from the 1966 model year through 1980. Before that came shorter serial numbers carrying very little about the car. From 1981 on, everything sold in the United States moved to the federally standardized 17 character VIN, a different animal with a different logic.

That middle stretch is the muscle car era, and it is why a Mopar VIN is worth reading at all. Those thirteen characters encode the car line, the series, the body style, the factory engine, the model year and the plant. A General Motors VIN of the same years encodes none of the last three, which is why a 1969 Road Runner says more about itself from the dash plate than a 1969 Chevelle ever will.

The plate sits on the driver side top of the dash, readable through the windshield from outside the car. On a 1968 or earlier body the vehicle order number is also stamped into the sheet metal in at least two hidden places. From 1969 on, those stampings carry the last eight VIN characters instead.

The Thirteen Characters, Position by Position

The first character is the car line. The second is the price class, which is really the series: E economy, L low, M medium, H high, P premium, S special, K police, T taxi. On a Plymouth B body, R and M together give RM, a Road Runner. RS is a GTX. On the Dodge side, WM is a Super Bee.

The third and fourth characters are the body style: 21 a two door sedan or coupe, 23 a two door hardtop, 27 a convertible, 29 a two door sports hardtop, 41 and 43 the four door sedan and hardtop, 45 and 46 the wagons.

The fifth character is the engine and the sixth is the model year, a single digit, so 8 is 1968 and 0 is 1970. The seventh is the plant: A Lynch Road, B Hamtramck, C Jefferson, D Belvidere, E Los Angeles, F Newark, G St. Louis, R Windsor. The last six are the build sequence.

The Fifth Character Is the One That Moved

For 1968 and 1969 the letters run A for the 170 six, B for the 225 six, D for the 273 two barrel, F for the 318, G for the 383 two barrel, H for the 383 four barrel, J for the 426 Hemi, K for the 440 four barrel, L for the 440 Magnum and P for the 340 four barrel. C and M cover a special order six or V8, and the 1969 A12 cars with the 440 Six Barrel went out under M.

For 1970 the deck was reshuffled. B is the 198 six and C the 225. G is the 318, H the 340 four barrel, J the 340 with three two barrels, K the 360, L the 383 two barrel and N the 383 four barrel. T and U are 440 four barrels, V is the 440 Six Pack, and the Hemi moved to R. For 1971 the set holds bar two changes: J drops out with the 340 Six Pack, and M arrives as the 400 two barrel.

Read a 1970 VIN off a 1969 chart and you turn a 340 Six Pack into a Hemi. That is not a rounding error. That is a different car.

Three letters do most of the damage. G is a 383 in 1969 and a 318 in 1970. H is a 383 four barrel in 1969 and a 340 four barrel in 1970. J is a Hemi in 1969 and a 340 Six Pack in 1970. Each swaps an entire engine family, invisibly, on a chart with no year.

The First Character Moved Too

Nobody talks about this one and it bites just as hard. B is the Barracuda in both 1969 and 1970, but in 1969 that is an A body and in 1970 an E body, two very different cars sharing a letter. J appears for the first time in 1970 as the Dodge Challenger, because the Challenger did not exist before then. X is the Charger from 1966 through 1970, and then for 1971 the Charger and Coronet were folded into one B body line under W, so a 1971 Charger VIN does not start with X at all. Our 1970 Charger year guide walks the same ground from the trim ladder end.

Where the Mopar VIN Decoder Charts Disagree

The sharpest example is on the Classic Industries guide currently ranking on page one. Its headline breakdown is labelled as the 1966 to 1970 format, and it teaches the fifth character with a shorthand saying J is the 426 Hemi and G is the 383. The worked example VIN printed alongside it is BS23J0B123456. The sixth character is a zero, so the car is a 1970. Under the 1970 codes, BS23 is a Barracuda in the Special series as a two door hardtop, and J is the 340 with three two barrels. BS23J0B is the documented VIN prefix of the 1970 AAR 'Cuda, of which fewer than three thousand were built. The example car is an AAR, and the chart above it calls it a Hemi.

The same page repeats the slip in its captions, and the pattern is diagnosable. It calls a 1969 Dart 340 engine code H, but the VIN it prints is LM23P9E, and P is the 1969 letter for the 340 four barrel. It calls a 1970 Challenger R/T 383 engine code H, but the VIN it prints is JS27N0B, and N is the 1970 letter for the 383 four barrel. Only its 1971 Demon caption lines up, because from 1970 onward H genuinely is the 340. The guide has taken the later letter and run it backwards through years where it meant something else.

Then there is the question of when the format even ran. One results page gives the 13 character VIN as a 1966 to 1970 system, a 1968 to 1980 system, a 1966 to 1975 system, and a 1966 to 1980 system split in two. One of those pages heads its code tables 1960 to 1976, six years before the format existed.

Even the enthusiast references contradict themselves. The Mopar Enthusiast Network publishes a separate breakdown for every year, which is the right way to do it, and its 1968 and 1970 pages both give R as the Plymouth Belvedere and Satellite car line. Its 1969 page gives K. Real 1969 Road Runner VINs start RM21 and RM23, so R is correct and the 1969 page has a slip, likely a stray paste from the price class column where K is the police code. Read the neighbouring years before trusting one chart.

What the VIN Will Not Prove

A Mopar VIN is generous by the standards of its era, but it stops at the engine. It does not encode the transmission, axle ratio, paint, interior, wheels or a single option box.

That work belongs to the fender tag on the inner fender panel, a different plate doing a different job, and to the broadcast sheet if one survived under the seat springs. Our fender tag guide covers those codes and the same year by year problem. Where real money rides on the answer, the route is still documentation checked against tag and plate together.

Run the logic in the right direction and it stays honest. A VIN that disagrees with the car disqualifies it. A VIN that agrees proves only that the plate and the car agree. More Charger coverage sits on the make hub.

One VIN Read All the Way Through

Run BS23J0B against a 1970 chart rather than a year blind one and it comes apart cleanly, position by position, as the box alongside shows. What it adds up to is an AAR 'Cuda, the Trans Am homologation car built for a single year, and not the Hemi car the ranking guide calls it.

Nothing in that string is ambiguous once the year is fixed, and everything in it is ambiguous until it is. That is the whole discipline. Get the sixth character, then read the fifth.

Frequently Asked Questions

Can you get a build sheet from a Mopar VIN?

Not from the VIN alone. Chrysler kept no public archive you can query, and no free tool produces a factory build sheet from thirteen characters. Original broadcast sheets survive inside the car, usually under the rear seat or beneath the carpet. Registries and marque specialists can sometimes match a VIN to surviving records.

Is there a free Mopar VIN decoder that works on classic cars?

Several exist, but most are built for modern 17 character VINs and simply fail on a 13 character muscle car number. The ones that do accept it usually run a single year blind table. Check any answer against a chart for that specific model year before you act on it.

How do you decode a 1970 Mopar VIN?

Read the sixth character first to confirm the year, then use the 1970 letters. For 1970, G is the 318, H the 340 four barrel, J the 340 Six Pack, L and N are 383s, T and U are 440 four barrels, V is the 440 Six Pack and R is the 426 Hemi. The 1968 and 1969 letters do not apply.

Does a Mopar VIN tell you the engine?

Yes. The fifth character gives the factory engine, which is more than a General Motors VIN of the same era offers. It gives the engine the car was built with, not the engine in it today. Check the block casting and pad stamping if the question is whether the car is numbers matching.

Sources: the Mopar Enthusiast Network year by year VIN breakdowns for 1968 through 1971; MaxWedge.com on plate and body stamping locations; the JEGS Mopar VIN guide for the 1981 changeover; and the Classic Industries and MoTales decoders, cited above as the pages the corrections apply to. The cover is an illustration produced in house, not a photograph of a specific car.