white smoke at high rms ?

this question isnt for my mazda but its kind of a universal question i have a 1978 trans am and when i rev it high it spits out some white smoke what does this mean
head gasket
leaned out
?
thankyou
derek

Smoke or water vapor? If an internal combustion engine is using oil or has blown a head gasket,it will usually smoke at any RPM, but usually at low RPMS.At high RPMs the extra fuel dilutes the oil or coolant to the point it cant be seen unless really high consumption.At high RPMs i/c engines produce lots of water vapor as a by-product of combustion.I bet that is what u r seeing.BJ