1-8-4-3-6-5-7-2 (counterclockwise at the distributor) 1-8-4-3-6-5-7-2 (counterclockwise at the distributor)
18436572
1,3,7,2,6,5,4,8 Counter-clockwise.
see link
the firing order for a Pontiac 400 v8 from 1967-77 is 1-8-4-3-6-5-7-2
1-3-7-2-6-5-4-8
If this is a 400 cu inch motor the order is 13726548. If this is a 460 cu inch motor the order is 15426378. The distributer rotates counterclockwise
1 8 4 3 6 5 7 2
1-8-4-3-6-5-7-2 distributor turns counter clockwise
The firing order for the Pontiac 400 engine is that the small block powers the big block.
Chrysler didn't have a 400 Cu In motor in 1963. The 400 didn't come along until 1972. So with that in mind, I suspect you either have a 383 or quite possibly a 400 that someone swapped in. In any event, the firing order for all Mopar V-8's (with the exception being reverse firing marine engines), is a counter clockwise rotation of 1-8-4-3-6-5-7-2.
18436572 clock wise
265, 301, 307, 326, 350, 389, 400, 421, 428, 455 all have the same firing order 1,8,4,3,6,5,7,2 the 2.8 firing order is 1,2,3,4,5,6