[AT] AC gas/diesel engine?

[JParks]

Education day for me!

I had a gentleman call me while ago who says he has an old AC crawler which
started on gas and switched to diesel.  (like the IH engines of the 40's
early 50's)

He said he had a model "S" crawler, which I also have never heard
of.......What engine did AC make like this, and what were the applications,
i.e. where used!?  (He could have said model "F" as we had a bad connection)

Thanks for any info

John Parks
Boise, ID