Which engine do I have?

While tearing down my new project I was looking to see if the engine serial number matched with the VIN. The VIN says the Jeep came with a 225. I found on the forum where to look for 225 numbers, but it was blank. Anyone know where to find the serial number for a 231, or if there is a way to visually identify a 231 vs a 225?

 

Looks like a 231 with the slanted valve covers. What is the firing order? That will tell if it is an odd fire or even fire.

 

Yup, 231 shown in pic. There are casting numbers in the back of the block above teh bellhousing iirc.

 

It is a 231, according to the data I found on this fine forum, thanks for Joel Vande Berg for compiling it, it is a 1979-81 V6 Even-Fire Turbo Charged. Obviously it isn't turbo'd and I don't plan on adding one. We found the block casting on the left rear side, running vertically just under the head:



Then we found the head casting number:



Now, on the top of the engine at the back just in front of the bell housing we found this one:



And on the intake manifold this one:



I am not sure about the last two numbers and what they signify, but since they were there I thought I would add them for curiosity reasons!

 

Then what is the difference? I thought it was the firing order...

 

When the firing occurs. The actual cylinder # order is the same.

 

Thanks guys for the explanation.