The engine number is stamped on the front of the block behind the alternator
The engine number is also stamped on the passenger side front spring tower.
Manual cars started with the letters GL...
automatic cars start with the letters GJ...
All XW GT engine numbers ended in a "C"
Windsor XW's up to December 1969, had a single small ID plate on the driver's side of the radiator support panel
From January 1970, the ID plate changed to the larger format and was located on the passenger side of the upper section of the firewall.
Additionally, a large proportion of the January 1970 cars had their plates mounted sideways, this changed quickly and from February 1970 the plate was mounted in its normal upright position.
Decoding the Body Prefix Number:
Prior to 1971 Ford used a dual numbering system.
They had a V.I.N. (Vehicle Identification Number) - which was the same as the engine number - stamped on the front edge of the passenger side spring tower
The body prefix and serial number - which also corresponded to the numbers stamped on the I.D plate - stamped on the passenger side front of the radiator support panel.
From January 1971 onwards, Ford went to a one number system, whereby the body prefix and serial number, as it appeared on the Compliance Plate, was the same number stamped on the engine and spring tower, (which by this time had shifted from the front, to the side facing the passenger front guard).
Body prefix numbers of Australian produced cars:
J – identifies the country of production (Australia)
G – identifies the assembly plant (Broadmeadows)
33 – identifies the model of car (Falcon GT Sedan)
A – identifies the year of production (See chart below for year and month codes)
B – identifies the month of production (See chart below for year and month codes)
12345 – is a unique number identifying each vehicle
K = Starlight Blue
R or 5 = Diamond White
G = Candy Apple Red
Y = Grecian Gold
M = Reef Green
Z or 8 = Silver Fox metallic
T = Track Red
S = Electric Blue
E = Polar White
F280 = Zircon Green
F289 = Surfer Orange
F117 = Brambles Red
F = Vintage Burgundy
B = Jet Black
V = Go Green
SPEC = Whatever You Like
T = 351 4V
H = 351 4V GTHO only
L = Four speed manual
B = Floor shift automatic
B = Black XT onwards
K = Dark Saddle XW only
2 = Cloth Inserts. This code followed the trim colour code eg B2 was black with cloth inserts