If there's a 20 degree bias not reflected in the tables then yes that makes a little more sense. But no the engine isn't DIS . It is an Iron Duke and some of the later car applications may have had DIS, but the trucks always had a dizzy. I do know that the pickup in these distributors had a conventional magnetic pickup and an optical as well. I'm not sure why exactly though. I think that the use of the optical pickup was why they used a '165 ecm though as there weren't any other 4 cylinders that used them. The other odd value was the spark reference angle being 89.75 degrees, but that may have something to do with the optical pickup. Thanks for the reply though, it makes me feel a little better about the wacky value. Oh, and I had named the xdf $85A2 because I had other files named $85A. Sorry for the confusion though