Max advance total (full initial + mechanical + vacuum) was 60° in the smog days. If you're lean enough* 50° min, 55° probably safe if it comes off at the right time. Lexus: slight momentary tinkle on transition is "normal and acceptable", but this on engines with knock retard.

* If it misfires reduce Holley mains by one and try it.


Boffin Emeritus