The larger engine was modified to have only four rather than eight main bearings.

In 1980, the engine was modified to run on alcohol (E100), and this option lasted to 1983.

This engine would be updated and modified several times, allowing it to remain in production into 1997.

It was making some progress but apparently the new engine was still being modified "for 190 miles per hour."

By 1948 the engine had been modified to produce a maximum of 275 hp at 8,000 rpm.

The engines cannot be modified, and they are sealed to make it easy to detect cheating.

The engines may be modified as allowed under different rules:

The engines used in the 1969 ceremonies were modified to resemble the originals.

To bring these planes into compliance, the engines must be replaced - which is expensive - or modified.

The third engine would be kept in place but modified.