IF you could spin the 14-8 at the same rpms then it would make more thrust. But if you're using the same engine then NO it won't work as it takes a lot more power to spin that extra 2 inches of pitch.

You need to balance the prop to the engine's max power point so it runs at it's best power outpu.

What most people do is trade off some diameter for more pitch if they want to go faster. The tradoff there is that the smaller size hasn't got the bite and acceleration is slower and the prop efficiency suffers. It's all about compromises and finding the "sweet spot"