Distributor recurve

rich006 said
Here's what I measured with the 1979 springs and governor plate in the 1974 distributor (vacuum line to distributor was disconnected and plugged). Initial timing was 10.5 degrees BTC. I only get 7.7 degrees of mechanical advance, which is all in by 1750 RPM. This doesn't seem right.

I agree.

rich006 said
And here's the vacuum advance chart for the 11.0R vacuum pod. There's no advance until vacuum is about 8 inches, and it maxes out at about 19 degrees advance (above initial) by 14 inches.

That seems to be working ok and pretty close to specs in the books.

So how to figure out what's going on with the mechanical advance.
??

Looking at the measurements and we see the advance begins above 1000 rpm.
Assuming the weights are moving freely, this indicates one or both springs is applying too much tension on the wieghts.
The long looped spring should apply no tension when the distributor is at rest.
So look at both springs, make sure they move freely and only the primary spring is holding the weight against the inside of the slot.

Then we see the advance slow greatly at 1250.
Its likely that's the long looped spring engaging. But best thing will be to take a look at the relationship of the springs and the weights.
Look at the inital postion, and then move the weight out until the second spring engages.

How to adjust the spring tension or degrees before the secondary spring engages
Distributor curve help needed

Thes two posts show what to look for
Distributor curve help needed
Distributor curve help needed