Initial timing

Sadly,
So much ignorance about initial timing. And how it behaves. I have just gone over this on another thread.
Millions of GM cars left showroom floors with well over 20* of initial timing. My GTO had 26*, many Chevs had 24*. If you had put a timing light on my car while in the showroom, it would have shown 26*. Dead stock engine, smooth idle @ 500 rpm.
It was done using Manifold Connected Vac Adv.
6* + 20* added when the VA was connected. The link in post #15 explains how it works.
Chrys missed the boat on this, it is that simple. Chr engines are no different to GM engines: they pistons that go up/down & valves that open/close.
Once the correct amount of idle timing is determined, THEN any combination of initial + MVA can be decided. Examples: 8* init + 22* MVA; 15* init + 15* MVA.
An adj VA unit must be used & most can add up to 30* of timing. A stop may need to be fabricated to limit VA plunger travel. Once static init has been determined [ say, 15* in example two ] the centri curve in the dist can be dialled in for WOT timing. It is all part of the tuning process & always amazes me how folks are quite happy to f*ck around with air bleeds & emulsion jet sizes....but spend no time on the ign timing that will have a great impact on drivability.