Originally Posted by Rick WI
That ignition curve is not setup with vac advance in mind, hence why I think he left it disconnected. If you connected the advance canister to manifold vacuum you would have way too much timing at idle, not sure if the motor will like all that.
Even hooking the vac advance to ported I think you may run into issues under light load throttle conditions with an over advanced situation given the very high base timing settings. Could be very prone to detonation.
So true cause I've been there, done that! Most rigs I've seen with a mechanical only distributor have a lot more cam...