Vacuum/Mechanical Advance Dilemma SB340

Without knowing what the cam really is, and where it’s installed it’s just a crapshoot.


Off the top of my head I’d say...... put a 10” converter in it which should really help with how the motor behaves at low speeds.

What the current combo wants is more timing and a quicker advance curve, but then it pings.

It’s hard to cover up a poor combo by just messing with the ignition curve.

The carb could probably benefit from being modified for 4 corner idle if it doesn’t already have it.
The carbs idle circuit needs to be on the same page as the cams idle requirements.

That 12” of vacuum...... is that in neutral at 1000, or in gear at 500?