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.
1-8-4-3-6-5-7-2. I miss mine!
18436572
The firing order for the Pontiac 400 engine is that the small block powers the big block.
18436572 clock wise
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 Counter-clockwise.
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
13726548 counter clockwise
counter clockwise 13726548--------------------------------------------------- Ford Firing Orderhttp://www.aa1car.com/library/ford_firing_orders.htm
The address of the Plymouth 400 Inc is: 134 Court St, Plymouth, MA 02360-8728
The 400 Ford has only one firing order and it is 1-3-7-2-6-5-4-8 which is the same firing order as the 302 HO, and 351. Rotor turns counterclockwise.
see link