Design Engineering Office

The fourth character in casting/part number prefix is for the Design Engineering Office that created the part.

A Light Truck Engineering Division
B Body and Electrical Product Division
C Chassis
D Overseas Product Engineering
E Engine
F General Parts/Electrical and Electronics Division
H Climate Control (1972-up)
J Autolite/Ford Parts and Service Division
L Industrial Engine Parts and Service
M Performance/Special Vehicle Operations (Incl. Holman Moody)
N Tractor Parts
P Auto transmission
R Manual transmission
S Light and Heavy Truck Special Order Parts
T Heavy Truck Engineering
U Special Vehicle Operations
W Axle and Driveshaft
X Emissions, Economy, Special Vehicle Engineering (Muscle Car Parts)
Y Lincoln/Mercury Service Parts
Z Ford Service Parts