How much Hp from 307 bored 040 over with 305 heads roller rockers and 268 cam?

Estimating horsepower for a 307 cubic inch engine bored 0.040 over with 305 heads, roller rockers, and a 268 cam typically yields around 250 to 300 horsepower. The actual output can vary based on factors such as tuning, exhaust, and intake systems. The combination of the larger displacement, improved airflow from the 305 heads, and the performance camshaft can significantly enhance the engine's performance. For precise numbers, a dynamometer test would provide the most accurate measurement.