Related Clues:

• Prefix with sphere
• Certain engine
• Prefix with spherical
• Half in front?
• Kind of engine
• Powerful auto engine
• Prefix with 48-Down
• Engine type
• Powerful kind of engine
• Spherical starter
• Half: Prefix
• Type of engine
• Powerful car engine, informally
• Half (Pref.)
• 50 percent (Pref.)