4.3L vortec EST ignition timing?

Just installing 4.3L V6 engine (1996&up model with balance shaft) with Edelbrock intake, Rochester 4Bbl carb and Delco EST ignition. As engine is from surplus stock, there no paperwork which states What is the correct ignition timing. According Delco manual Base should be 8 and TA 26 but it says that check from manufacturers manual.
According Volvo or Mercruiser manuals there’s many different figures. What should be the correct timing for that engine?

The correct timing is driven by how the engine is built and who built it.

that said, the max advance of the EST system is controlled by the module inside. My preference is to verify the advance function works and them set the timing at max advance and live with the initial value....start on the low side and see how it works...and then increase it slowly, if you want.

makomark said:

The correct timing is driven by how the engine is built and who built it.

Click to expand...

well, this is unfortunatly unknown, lot of engines was sold from bankrupted Boat repair company without papers...

what makes a difference between GM V6 engines used by Volvo, Mercruiser or OMC? If you look parts catalog, then all parts are the same for same block and head #. As I see the difference is what kind of distributor they are using.
is there different advance modules used for EST distributor? If i start with 8 on base mode it gives 22 at idle and max 30 around 2000-4000RPM. Does it mean i should start with 2 degrees in Base mode and end up with max 26 as stated in EST manual?
Thanks for all kind of information