Historical clue formulations

• Motor with some muscle — 2014-03-16
• Engine type pioneered by the Buick Special — 2011-10-17
• *It may be under a hood — 2011-01-23
• Kind of engine — 2011-01-19
• Midsize motor — 2006-10-04
• Midsize auto engine — 2004-11-25
• Auto engine type — 2003-03-18
• Powerful auto engine — 2002-08-05
• Motor with some oomph — 1999-02-28