help its smoking 240 73'

hi,

befor i did anything the engine was running fine....

i put some mystrye oil in the crank case and some gas treatment in.. now it is smoking ... the color of the smoke is white.. so its the gas right..? as i rev it up>> it smokes out a ton and some comes from the engine conpartment... also its leakin oil from some where... i jacked it up and it was driping from the exhouast pipe connector that runs in to the header... ithink is driping from some where on to that.... my dad said its not B/C of what i put in it.... but idk.....#@#$?

steve