What would be a likely consequence of installing a new camshaft incorrectly?

Installing a new camshaft incorrectly can lead to poor engine performance, which is the correct choice in this context. The camshaft plays a crucial role in the timing of the engine's intake and exhaust valves. If it is misaligned or incorrectly installed, the timing may be off, resulting in valves opening and closing at inappropriate times. This can hinder the engine's ability to properly intake air and expel exhaust gases, leading to a variety of performance issues such as misfires, decreased power output, and rough idling.

Additionally, although decreased fuel efficiency and increased engine vibration can occur as well, these symptoms are often secondary effects of the underlying poor performance. Improved horsepower would not typically result from an incorrect installation; rather, the intended performance enhancements from the new camshaft would be compromised, leading to an overall decline in engine function.