Mopar Engine I.D.

For the most part, muscle cars have lead rough lives. Face it, people didn't pay the extra dollars charged by the factories for more horsepower simply to motor between the grocery store and the dry cleaners. No, when a factory hot rod was ordered -- it was invariably run hard (if not by the owner then the owner's children, sorry dad). And cars that see years of hard use tend to break parts. Parts like engines, transmissions and rear ends.

So now, some 25+ years later, there's a very good chance the original drivetrain in your particular muscle car has been changed. But how would you confirm this? By checking the "numbers", of course. You may have bought your car based on the promise by the previous owner that it was "numbers matching". But unless you've checked them yourself, you really don't know, do you? (Unless, of course, you're the original owner -- but how many of us can say that?)

So the questions become: What is numbers matching, why is it important and how is it verified? In a nutshell, matching numbers refers to the various casting numbers, codes and dates found on all the major driveline components (engine, transmission, rear-axle assembly). On later models, the engine block and transmission carry the V.I.N. number as well as the part number and i.d. codes. But it doesn't stop there.

Each engine, for example, had a particular carburetor, distributor, set of cylinder heads, etc. for that combination. The true numbers matching car will also have the correct engine components as well. But unless you're building a concours show car or paying six figures for a Hemi Cuda convertible, most enthusiasts aren't overly concerned with carb and distributor numbers. The proper engine numbers are what most of us are concerned with.

Why are matching numbers important? Well, unless you've paid a premium for a numbers matching car, or are planning on entering a concours show, they're probably not. If you're planning on simply driving and enjoying the car, it really doesn't matter if the 440 is a '69 or a '70 model. But, given the price differences (and resale value) between a car with the original drivetrain and a car without, it pays to know how to tell the difference.

But before we get into finding and decoding the numbers, we'll give you a little Chrysler engine history. If you've got questions that aren't addressed in this article, feel free to give us a call, we'll help you any way we can.

To get things started we're going to give you a little history about some of the major engines that you will find in your muscle car. 1958-74 Chrysler engines divide into several catagories. First is the "slant-6", also known as "G" (170 and 198) or "RG" (225) engines. Next is the "wide block" or 1957-66 318 "A" engine. This engine faded away as the muscle car era came into full swing. Third is the small block "LA" engines which include 273, 340, 360, and the 1967 to present 318 (which has nearly nothing in common with the 1958-66 318 "A" engine). Fourth are the big-block engines which include the B-series consisting of the 350, 361, 383, and 400 engines and the RB-series which includes the 383(RB), 413, 426 Wedge, and 440 engines. Finally, there is the 426 Hemi which is its own animal, and is not to be confused with the 1951-58 "Old Style" Hemis. The old style Hemis had the distributor in the rear instead of the front like the 426 version.