86 MC SS timing question

I tried to set the timing to 0 and it ran very bad and stalled. The only way it runs decent is to advance it well ahead of the timing marks. To set the timing on this 5.0 is there anything I must disconnect first? There is no vacuum advance. Reply to [email protected] if you can.
Thanks

Timing on a stock 4th Gen (83-88) SS is 6* BTDC. The distributor advance is computer controlled so you do need to fist disconnect the 4-pronged connector coming from the Distributor (should run along the drivers side valve cover). You only need to set the initial timing.