could you tell me what this wire is? its source is from under the distributor. (from underneath distributor.. to a harness.. then to the cut wire)

 

the engine is a '00 ls b18b1

 

Judging on color, probably ground.

 

Like qtiger said, the black wire is probably a ground. The rest of the wires in the loom you'll have to figure out though, because the car won't run with a disconnected distributor.

Might I ask why that was cut in the first place? Is this a swap engine?

 

i was also thinking it was a ground wire.. yeah, the engine is a swap