Answer:

VSIX

Answer	Crossword Clue
VSIX	Midsize engine
VSIX	Innovation in the 1962 Buick Special
VSIX	Midsize auto engine

VSIX	Engine spec
VSIX	Common auto engine
VSIX	Type of engine
VSIX	Motor with some oomph
VSIX	Powerful auto engine
VSIX	Auto engine type
VSIX	Midsize motor
VSIX	Engine type pioneered by the Buick Special

VSIX	Kind of engine
VSIX	Motor with some muscle
VSIX	Engine size
VSIX	Engine type
VSIX	Rather powerful engine