The 230ci Flat Head Six had a long run in Dodge trucks and cars, it was used as far back as the early 40's as a truck motor, and when the big trucks went to the longer 251 style block, cars got the 230. By 1961 it was all over, most cars and trucks used OHV slant sixes, but as a friend of mine always says, OHV are a passing FAD!

The 230ci flat head six was used from at least 1946 until 1960 in Dodge trucks, though up to 1955 it was only used in the 1 tons, and bigger. The lighter duty trucks used the 218ci flat head six from the early 40s, until 1955. The 230 and the 218 are very similar motors, the main difference being the stroke, if you put a 230 crank and rods into a 218, you will have a 230. Now if you were a flat head expert, you could tell the difference between the 230, and the 218 from small clues on the engines, but for the purpose of this webpage, I will consider them the same for description purposes.

A 230ci flat head has a 23" long head, unlike the 265/251 which has a 25" long head. Post war Flat Heads generally have the build date cast in just below the distributor, so if your motor is dated after 1955 and has a 23" long head, then it is most likely a 230ci motor. The numbers listed below are a good beginning guide, but as the 23" long block was used for so many years, in so many applications, I do not have a comprehensive listing yet.

If you have any info to share on flat head engine numbers, I would be interested in hearing it, as I would like to create a database off a flat head engine numbers, so a person could figure out what their engine came from if it is not the original one.

I have done some research on flat head six engine numbers, and I have found some funny things, first, the factory manuals, and the Dodge Truck books that have been written in the last few years all use the same numbering system to tell you what year, and model of truck a motor came from.

This makes sense, as the newer books used the original literature as reference material. I got my information a different way, I went out into the field, and looked at actual trucks. I checked the engine number, compared it to what the books said, and when it did not match I went looking for a reason. Sometimes the engine had been replaced, but I kept getting to many numbers that did not match the books, and yet matched several other trucks of the same year.

For example, the books claim that a 1959 W100 with a 230ci flat head six should have the following number on the engine:

M6 W1-1001 (1001 is the starting number, it would count up from there)

I have found that ALL the 59 Dodge trucks, D100-D300, and W100-W200 equipped with the 230ci flat head six that I have checked, have the following number:

M23 1001 (1001 is the starting number, it would count up from there)

When I also found the 58s that I checked had L23 1001 I figured I was on to something!

So I started to check every 230ci flat head I could find in a 57-60 truck, and I kept finding the same numbers over and over again.