This maybe a stupid question. But whats the difference between a small block and big block??...Also,I have a 350 supposedly new or rebuilt??(just bought from a girl that didnt know much about cars-or that she was getting ripped off)wich leads me to suspect that the thing was even put back together right!Or even really "rebuilt" One main reason being that it uses about a quart of oil every 250 miles..the other being that when I accellerate quickly I notice smoke thats sort of whitish colored coming from the tailpipe..it isnt blue like oil so I'm just wondering if its normal exhaust being expelled from the pipe??..So I guess what im asking, is that if anyone knows of any other reasons a motor would use oil and not overheat or give any real signs or head dammage etc. i.e. overheating???Any and all input would be greatly appreciated to help me figure out whats wrong! thanks!