How to find the best ignition timing position without a dyno?

[JohnL]

I know! I was like,why hasn't my motor blown up!

A retarded ignition timing (over ideal) is quite mechanically safe for the engine (no expanding flame fronts / pressure rise colliding with still rising pistons), though it might cause the exhaust valve to run hot if fuel is still burning as the exhaust valve opens.

It's been like that for 1 yr and 9 months now.That's how long this problem has been hanging around.

I can't wait to drive my car home 2night from work

It ought to be substantially improved, and with better economy. You need to ask why was it so far off?