Black soot or oil from exhaust at startup

[jp_waltz]

So I just picked up a 1970 40 and when it's cold or not completely warmed up it spits out some kind of black soot or maybe oil. It's getting all over the driveway. The motor was rebuilt a while back according to the PO and it sounds like he put a race cam or something in it. It also has an after market carb(not sure of the make) and it came with a brand new weber carb. Any ideas as to what the black stuff might be and how I can mitigate it?
Thanks
Paul

 

[JohnnyC]

IMO sound like your running rich and its just spitting out carbon soot with moisture out the tail pipe