What To Disconect To Set Timing On 4.9 Motor

You don't disconnect anything. Get yourself a timing light. Connect the power clips to your battery and the other clip over your #1 ignition wire. Check timing on harmonic balancer. If it need adjusted loosen the distributor hold down clamp and very slowly turn distributor one way or the other. Tighten clamp.

You need to set the computer into base timing. Pull the green plug near the distributor. Then set the timing at idle speed.