Depends upon the year, and which 396 it is, but, 4, to 8 degrees advanced, or BTDC, should make it run best.
6 degrees advanced, or BTDC.
Right around 6 degrees advanced, with todays pump gas.
12 or 13 degrees
6 degreed advanced or BTDC.
I would set it by ear, and performance.
To advance the timing on a 396 Chevy, you should turn the distributor counterclockwise. This adjustment will cause the ignition timing to occur earlier in the engine cycle, which can improve performance. Always ensure that you check timing specifications and use a timing light for accurate adjustments.
a Chevy 396 bear block ways, right at 200 pounds.
Yes.
about 685 pounds dry
yes
180, to 200.
No it is not an interference engine.