Stop in for a cup of coffee

Set the timing and dwell yesterday. Been thinking about it since and did some internet reading because I'm plain clueless for the most part.
First, using the cool analyzer Ray sent me set the dwell to 30. It was at 33. Sounded and ran SO much better doing that.
Next put a piece of tape at 0 on the damper, pulled the advance hose off the distributor and plugged the hose.
Ran the warm engine at idle (850 rpm) turned distributor to read about 12-13 btdc. This engine calls for 12 1/2.
It just didn't seem to run right knocking, took it for a spin not happy.
Turned it up to 8 btdc and it sounds a lot better. At 3500 rpm it dropped to 12-13 btdc. Test drive better starting to smile.
Just for fun tried it at zero sounded good, but ran like crap.
I read where it says timing an older car can depend on age of the engine, miles, timing chain age, rebuilt with what, and so on.
I guess what I'm asking is 8 ok?? Can there be other factors involved to determine the right setting??
That doesn't sound right. All my 383's liked 10-15° as long as it doesn't ping or kick back against the starter it's usually good. I put 15° in my 318 and it likes it except for the fast advance which makes it ping. :BangHead: