This is what i've personally learned about smoke from a tail pipe:
Blue is oil, whether is leaking past the rings or the valve guides
Black is excessive fuel
Whitish/gray smoke usually either a blown headgasket (huge amounts of smoke) or condensation thats evaporating, or just normal exhaust on a cold day.
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previous name: 84stangLX
'84 Mustang 5.0 LX
my LX
'89 Mustang GT
my GT