Complex sentence: Browning hired two Lockheed engineers, Pete Law and Bruce Boland, and a team of other specialists made major modifications to the plane, including installation of a Rolls-Royce Griffon engine and contra-rotating propellers.
Split into simpler sentences: Browning hired two Lockheed engineers, Pete Law and Bruce Boland, and a team of other specialists to make major modifications to the plane. This included installation of a Rolls-Royce Griffon engine and contra-rotating propellers.