In 1965 the 197-hp V-345 V8 was added, along with the Allison 6-speed automatic transmission. Heavier optional front and rear axles in 1966 raised the capacity ratings to 24,000 lb GVW and 40,000 lb GCW. The smaller 6-cylinder gas engines were discontinued in 1969 and only the BD-308 was left for die-hard 6-cylinder fans. In 1971 the V-266 V8 and D-301 diesel were dropped.