The 1966 B1500/Proceed presented in October 1965 used the same 1484 cc OHV I4 engine as its predecessor, with minor changes to the cylinder head and valves and the use of a downdraft carburetor instead of the sidedraft unit used on the models sold between 1961 and 1965. The UA engine now produced at 5200 rpm. The chassis was now called the "BUD61"; it was longer than its predecessor and received new bodywork of a squarer design, and four headlights. In January 1971, a 1600 cc model with the chassis code BNA61 was introduced. This had 95 PS SAE in global markets; US brochures did not specify its power output and European importers claimed DIN. In Japan, a minimum (SAE gross) was claimed; the model was advertised in Japan as the "GT-Truck".