Initial timing

30* @ idle can be too much.
Or it might not be enough.

Over cammed 273. Would not take much to over cam a small engine like the 273.
But help is at hand!!
Here is how to determine initial timing for that combo:
- disconnect & plug VA unit.
- get engine warmed up, idling, in gear if auto trans.
- loosen dist clamp, turn dist slowly to advance timing. Keep advancing dist until rpm peaks. toggle dist to make sure you have the highest rpm.
- now check what the timing is. That is what THIS engine wants for best idle AND tip in response. If you use vac adv connected to man vac [ MVA ], you can use any combination of MVA + init. Example: best idle was @ 36*. You could use 18* init + 18* added by VA.

An engine I tune for drag racing reqd 53* for best idle with one of the cams we were running.
Just an example.