What is the firing order and location on distributor for 1-8 on a 1991 E-350 Ford van with a 351 cubic inch engine?

the firing order of your van is 1-3-7-2-6-5-4-8 in a clockwise distributor rotation, the right side as you sit in the vehicle being numbered 1234, the left 5678 from front of the engine towards the back