What is body harness connector? May be main harness connector?

[xagna]

I am coming to finish the KA singlecam to KA dualcam swap.

Reading over 240sx.org's singlecam to dualcam swap guide, I found this.

"Wiring:1. Locate the body harness (under dash harness that attached to the ECU) that attached to your old harness. Cut the old connector off (the one that attached to your SOHC harness) and attach your DOHC body harness connector. Just match the colors!Yellow/Red --TachYellow/Green--SpeedometorOrange--Ignition startBlack---GroundBlue/Black---Water temp sensor"

Is the body harness "main harness" as called by the FSM? Can't find a harness called body harness in the FSM. And is it that the singlecam connector M53 and dual cam engine harness' connector F1 are not compatible?