That sounds like the same one that I have. I have a timing light that has a timing dial on the back of the gun. Use the dial to set the timing mark to zero and then check the dial on the back of the timiing light. That is what your timing is. Mel just told me that the timing should be 8 degrees before top dead center at 2000 rpm. That is from memory, double check that number. No matter what you do you should check with Mel, he is the timing guru.
Good luck,
Doug
'86 F-250 4x4
'89 E-250 ATS