1968 340 timing
My suggestion is to measure timing from the lowest rpm to the highest timing/rpm you can measure with whatever you have on hand.
Write down each measurement and plot on the timing graph. Use the 273 non-emissions graph as a reference.
Since it was converted to an ECU, clearly the distributor is not the original.
So the only way to know what the advance looks like is to measure and plot.
You can also look to see if the distributor still has its tag. The tags are held onto the side with a screw like this.
MP ones are often colored green.
One final thought. Initial should always be measured with the vacuum advance line disconnected and plugged. You prob know this but a lot of people don't. Golf tee is a good hose plug.
My suggestion is to measure timing from the lowest rpm to the highest timing/rpm you can measure with whatever you have on hand.
Write down each measurement and plot on the timing graph. Use the 273 non-emissions graph as a reference.
Since it was converted to an ECU, clearly the distributor is not the original.
So the only way to know what the advance looks like is to measure and plot.
You can also look to see if the distributor still has its tag. The tags are held onto the side with a screw like this.
MP ones are often colored green.
One final thought. Initial should always be measured with the vacuum advance line disconnected and plugged. You prob know this but a lot of people don't. Golf tee is a good hose plug.