Here is all the info you need;
Both of these apply from 1968--1992
HO 302, 351, 400, engines---firing order 1,3,7,2,6,5,4,8 counterclockwise with #1 on the cap at the 1-oclock position in front of the radiator.
Non HO 302, 351, 400 engines---firing order 1,5,4,2,6,3,7,8 also counterclockwise With #1 on cap in the same position as above.
cylinder ID and arrangement are the same for both situations
R/S (passenger side) cylinders from front to rear 1,2,3,4,
L/S (driver side) cylinders from front to rear 5,6,7,8,
This is all stock of course.
Hope this helps. Good luck,