1 - 3 - 7 - 2 - 6 - 5 - 4 - 8
The distributor rotor turns COUNTERCLOCKWISE
The marked # 1 position on the distributor cap faces to the REAR and slightly towards the drivers side
The engine cylinder / spark plug locations are numbered :
firewall
4 - 8
3 - 7
2 - 6
1 - 5
front
1-3-7-2-6-5-4-8
Firing order is : 1 3 7 2 6 5 4 8
Google search - 351M vacuum diagram
http://boxwrench.net/specs/ford_351C.htm
351w,351m,wiring and distribution fireing order=1-3-7-2-6-5-4-8
351W (5.8L), 351M, 400 and 1994 and later 5.0L V8 Engines... 1-3-7-2-6-5-4-8
of course.
need to know the spark plug gap for a 1979 Mercury Grand Marquis with 351 modified.
if it is the stock engine then it is not a 351m because ford had stopped making the engine before 79
Counter-clockwise 1-5-4-2-6-3-7-8 Number 1 plug is located passenger side front. If this is not the OEM engine or the cam has been changed then this firing order does not apply and it may be Ford (5.0L HO, 351W, 351M, 351C, 400): Counter-clockwise 1-3-7-2-6-5-4-8
Yes. basically the 351m is a Cleveland with a modified deck height.
firing order is as follows for 5.0L and 7.5L engines from 1994 and earlier. 1-5-4-2-6-3-7-8. 4 8 3 7 2 6 1 5 Distributor rotates counter clockwise. firing order is as follows for 351M, 400, 5.8L and 1995 and later 5.0L engines. 1-3-7-2-6-5-4-8 4 8 3 7 2 6 1 5 Distributor rotates counter clockwise.