the whole harness should plug and play allright, but the only thing i can think of is that idk exactly how the vtec wires are ran on and obd2 vtec harness (as in the vtec wires pin locations in the harness)
because the obd2 ls harness has the crankshaft fluctuation sensor wires where the vtec wires should be, and idk if on the vtec harness the vtec wires are in a seprate plug or if they re incorprated the vtec wires where they were before and made the crank sensor a seprate plug, dosse this make sense?
if i were you i would make your sohc vtec harness work, that way you have no worrys of any of this, you may need to change/ lengthen a few wires, but all in all it should work (i have done this countless times), if you use your obd1 sohc harness you may need to change your injector clips to obd2 this will take care of lengthening them as well...
and you may need a dist. adapter if you use your obd1 harness
http://www.jegs.com/i/MSD+Ignition/121/8864/10551/-1 <- like this one, you only need it if you use the odd1 harness though
if you could post up pics of the shock tower plug on the passenger side/ecu side of the car in the engine harness, like a good close up pic, and one kinda further back i may be able to see the wire color and tell you if itll work or not
