Holley/Mopar '6160' carb

I wondered the same thing, this carb ran pretty rich on my old worn out 318 so I wasn't sure what to expect. I think the jump to 370 cubes (360 .060-over) and 10.5:1 compression made a big enough difference in airflow...

Anyway I swapped the step-up springs today and that definitely made a difference, you can feel the point when you reach the vacuum where the metering rods change height. I think it runs a little lean on the 'cruise' step but once the 'power' step comes on it pulls REAL hard, you can even hear a little change in tone of the engine with my loud mufflers (SO COOL lol). That's OK with me since I want to cruise a lot anyway and would like to save gas however possible.