4150 has 2 metering blocks, 4160 has a block and a plate that cant be seen so the bowl attaches directly to the main body. Truck carbs usually had less emission fittings on them and were jetted fatter. They should have been an the smaller side considering truck motors were more low end power rther than high end breathing. That 76 427 was only used in a Kodiak or a Top Kick medium duty truck, and I bet those motors never saw more than 4000 RPM. May want to start from scratch on that carb, I mean look up jetting and metering for a 66 L72 corvette or Camaro and start from there. Governed most likely means that there is a throttle stop on the carb itself for those big box trucks. I would look further for a "Normal" 4150/4160 3310. They can be had for less than 150 and in sdtreet trim too, not 5 ton truck.