How to ID 401 in an FSJ?

[tom85cj7]

Is there an easy way to identify an AMC 401 in a FSJ other than looking at the numbers on the block? What is the VIN code and digit? What years had the 401 as an option?

Thanks,
Tom

[woodybeone]

Hi Tom,
There is a wealth of information compiled in the "Technical Library" section of this site.
Here is what your looking for (http://www.ifsja.org/tech/figures/index.shtml)

[bvibert]

You can tell if a truck is supposed to have a 401 from the VIN, but I wouldn't rely on it. These rigs have been around for a while and many of them have had engine transplants at one time or another. I've gotten a couple of 304's that I thought were going to be 360's :( luckily they were pretty much free so it didn't matter much. The only sure way is to check the casting on the block behind the motor mounts. I've also seen trucks that were supposed to have a 304 and ended up having a 360, so you could get lucky...