[LS1Racer]

Correct., Crank reference settings are important for this setup, on the opti dist rotor phasing is kind of set.
This is from BS3 site, I clipped the part out for what you were asking.

Type 3 - MSD Distributor Used to Only Distribute Spark from an MSD 6A/7A/8… box, with a
Crank Trigger.
Using a crank trigger and a CDI ignition module, like an MSD 6A, a distributor can be setup to just
distribute spark, when used in conjunction with a crank trigger.
Quick Setup Guide
• Find TDC, cylinder number one (1), compression stroke. See Find_TDC on page 20.
• Roll the engine back to 50o
BTDC.
• Install the crank trigger making sure the arrows on the crank trigger wheel are going on the
correct direction! See Crank_Trigger_Considerations on page 21.
• Line up the crank trigger sensor with the magnet in the wheel. Connect the red BigStuff3 wire
to green crank trigger wire. Connect other crank trigger wire to BigStuff3 black wire.
• Roll the engine back to the position BTDC (cylinder 1) equal to the max power timing.

7
• Install the distributor then “bump” the starter until it engages the oil pump drive while applying
a light downward pressure. Once the oil pump drive is engaged, rotate the engine back to the
timing mark on the dampener that will represent the maximum timing the engine will see at full
power. Turn the base of the distributor so that the distributor cap terminal for cylinder number
1 is aligned with the rotor in this position. Tighten the distributor down.
• Connect the BigStuff3 points wire (white) to the MSD ignition box points input.
• In the BigComm Software (Operating Configuration), set the crank reference setting to 50. See
Setting_The_Crank_Reference on page 25.
• Start the engine, with the engine still running verify that the BigStuff3 “Dash” timing advance
value equals the timing value seen (with a timing light) at the crank. Change the crank
reference value in the Crank Trigger window (in the Operating Configuration table), up or
down, until the “Dash” value and the crank value are the same. See Dash_Window on page 29.
• Dynamically check the rotor phase. See Dynamically_Checking_Rotor_Phasing on page 30.
• Lastly, you will want to verify cam synchronization. See Verifying_Synchronization on page

I have a gutted opti distributor with new MSD Cap and rotor that we used before in the parts for sale section if you are interested.
Hope this helps.