I will bet you that it doesn't. Not factory anyways.
If it does have a ford 390 ,It is a transplant. More likely a 392 IH engine in it and they think it is the same as ford because the dizzy is in about the same place as a ford.

I think the Ford an Binder distributors sit straight up an down . You could call and play dumb and ask a few questions about the dist . If its on an angle to the drivers side it could be gold . I got an orange binder 4oh1 an 727 in my garage from a 71 - 73 Scout ..77.

A friend of mine put a 455 Buick in a Wagoneer just to mess with everyone. It eventually lost the trans and was parked, he moved, and it went away. Can you imagine the confusion he created for the next owner down at the parts store?  

International made their own 4 cylinder and 8 cylinder engines.  They used AMC 232's and 258's for their 6 cylinder options.  In 76 they started offering a diesel in their Scouts (which is what my 77 has), but they didn't manufacture a diesel small enough to fit in Scouts at the time, so they purchased (follow this if you can) Chrysler Marine Nissan Diesel engines to adapt into them.  They also briefly used some AMC 401's when they ran out of 392's in the early 70's.
 
It's a pity IH and AMC were competitors rather than allies, their companies had a lot in common with each other.  The experience I get driving my Scout is very similar to driving my Rebel in that I get Jeep'ed and Bronco'ed all the time, and when people do recognize it, they are very appreciative.  I also had the great experience recently of calling my insurance about a flat tire and having to explain to the young lady on the phone what and International Scout is and who manufactured it...