A series 318 cubic inch V8, also called "Polysperical"

The A-Series 318 V8 is the first in a long line of 318ci V8 motors for Dodge, it was the direct replacement for the 315, and while the original design 318 only lasted until 1967 in Dodge trucks, it spawned a long running lighter version of itself, the LA-318.

The A-Series 318 was used in Dodge trucks from 1959 until 1967, and in Dodge cars for much of that time, they were also used in industrial applications, like farm equipment.

There are many variants, but to my knowledge they share many of their components, and any A-series 318 can be bolted in place of another. The only problem being an automatic motor needs a different pilot bushing if being used with a stick.

Engine Numbers

The numbers that I can find in the various books that cover Dodge trucks do not match what I have found by checking engine numbers in the field.

Below I have a chart of what the books claim, and what I have found in the field.

There are a few exceptions to the info I listed as having found in the field, but as I have only found one or two motors with these exceptions, I can not be sure of them yet. For example, I found a 59 W300 with the number, P31-425743B, and a 60 W100 with the number P31-092897, neither of these trucks is definitely original, and so I am reserving judgment until I see a few more trucks with this number. As they were two different year trucks, it is even harder to classify.

I welcome any engine numbers that you have checked from this era truck, and any corrections you may have in my statements.

  What the books claim What I have found in the field.
W100 M8 W1 1001
W200 M8 W2 1001
W300 M8 W3 1001
D100 M8 D1 1001
D200 M8 D2 1001
D300 M8 D3 1001
All the 1959 D100-D300s, and W100s and W200s that I have checked were stamped TMP8 016096, with the sequential number changing. I have not yet found one that has any relation to the numbers claimed in the books.

All A series 318s in all models of truck:

TP 318 8 3 1001

T=Truck, P= P series, 318= 318ci V8, 8=month made, 3=day made, 1001= sequential number.

All the 1960 D100-D300s, and W100s and W200s that I have checked were stamped P318 060134 , with the sequential number changing. I have not found one yet that started with a T, or had the date laid out.
To find your engine number please look at the pictures below. You will see in the first picture that the engine number on a 318 is located just below the head, on the drivers side of the engine.
Follow the blue arrow to where the engine number is stamped
Here is a closer shot of the engine number location, you should just be able to make out the number now, right below the point of the blue arrow.
Here you can see the engine number, this engine was in a 60 D100, and the number is P318 211527. This makes it a 1960 A series 318, but if you look at the chart above, does not quite match what the books say.
I am always looking for more information on 318 V8 engine numbers, so if you have a 59-60 Dodge truck with a 318 V8, please check your number and E-mail me at Thanks!