Hey
@nzlandcruiser, nice truck.
The 1972 - 1974 model years in saw a lot of changes. In the Aus/NZ markets they were most notably: 3 speed > 4 speed. Two-piece doors to single-piece doors. Single lens indicators > dual lens. F engine > F.5 engine. Single circuit brakes > dual circuit. Integrated steering column and box > two-piece column and box. Lap belts > lap sash [fixed, not retractable].
Essentially at the end of 1971 the 40 series sported an F engine [usually an F145], J30 trans [3 speed], single-circuit manually brakes, ribbed dash, overhead wipers, two-piece doors, integrated steering column and box arrangement, lap belts, single lens indicators with amber lenses and indicators on the aprons, rectangular mirrors that bolted to the cowl [pax side optional!], more common to see 3.70 axle ratios and some 3.36 [super rare].
By 1975 the 2F had arrived, you got a FF rear axle as standard, curved firewall rib for the boosted brakes on two circuits [this rib arrived and of 1971], flat stamped dash, wipers down below, mirrors on your doors [the squarer plastic variety that are the most recognisable], dual lens indicators, 3.70 axle ratios far less common and some other creature 'comforts'. Where and when these changes occurred has a general pattern but there are anomalies.
I guess what I'm getting at with all this is that the changes between 1971 and 1975 are often not as rigid as the changes between other major developments in the 40 series run. Couple that with the mods people do to these things over their life and it can be a it tough to tell. Spector Off Road has an engine number chart that may help date your truck but then again your engine could not be original to the truck.
When you dig into overseas markets that have less demanding clientele than Aus/NZ/USA you get some interesting combinations, like SF rear axle FJ62's in 1989 and J30 equipped FJ40's in Africa in 1983 but with the later steering wheel and FF rear axle.
Hope that helps.
