I'm not a mechanic / technician but I would assume the engine cylinders for
a Ford 6.9 liter diesel V8 would be the same as a Ford gasoline V8 :
firewall
4 - 8
3 - 7
2 - 6
1 - 5
front of vehicle
cylinder # 1 is the front cylinder on your straight 6
The # 1 cylinder for the 4.9 L ( 300 cubic inch ) straight 6 cylinder Ford is the cylinder at the front of the vehicle
# 1 cylinder is the front cylinder on a Ford straight 6 cylinder engine
For your Ford 4.9 liter / 300 cubic inch inline six cylinder engine : ( the # 1 cylinder is at the FRONT of the vehicle )
# 1 cylinder is at the front by the radiator on the Ford 300 cubic inch straight 6 cylinder
Six cylinder
firewall 3 - 6 2 - 5 1 - 4 front
would be the 1st one closet to the radiator ======================================================= On a straight ( inline ) 6 cylinder , the Ford V6 with rear wheel drive / 4X4 is : firewall 3 - 6 2 - 5 1 - 4 front
Closest to the front of the vehicle
firewall 4 - 8 3 - 7 2 - 6 1 - 5 front ( Ford V8 engine ) also , for the straight 6 cylinder engine , the # 1 cylinder is at the front
Yeah. They made impalas with 6 cylinder from 58 to 69
1----2----3 4----5----6 ---front---