Tonight I was letting my 67 camaro run for a while since its been cold out and I don't want it to just sit, but my dad decided to rev the engine up and apparently got a little carried away. When he rev'd it up, a large amount of dark black smoke came out of the left tail pipe. My question is this, could it just a bad seal somewhere and its burning oil? or would it be something worse? I don't have a tach in it yet so I don't know what rpm he got it up to, but I must say I wasn't too happy about it. Should I even try starting it back up or be thinking about taking it into a shop to be looked at first?

 

Black smoke is usually an indication of an over rich fuel mixture. Oil burning produces a blueish smoke.

 

+1 ^^what he said

 

Perhaps a plug not firing well and your dad cleared it out. Check the condition of the plugs and see how they look. Dual exhaust/mufflers? one side may have just been loaded up.
Kudos to pops for throwing revs!

 

a wild guess ... Holley Carb? Sick