75 and older have intake and exhaust both on the driver side (in the US anyway) or on the left side of the truck if you are sitting in the cab. The valve covers look quite a bit different too, black painted sheet metal is 76 and newer, unpainted cast aluminum is 75 and older. I bet if you look in the gallery on the main luvtruck.com site here you can probably find a 75 or older motor picture to compare.
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95 Isuzu Trooper Daily Driver
86 Isuzu Trooper reliable backup
77 LUV 2wd stock beltway blaster (resting)
79 4x4 LUV project: 2.6L, 5spd, 31s (eventually)
MEPR: Man, my 4x4 makes all other LUVs look good
