Setting the timing on a 69 318
Some really good advice here, especially to check the timing from TDC and the entire curve.
Assuming the original factory distributor, it has 5* ATD as the spec because the primary advance curve is very fast and long. 0* TDC is 5 degrees more and that's about the limit of what you can add to initial if the fuel allowed it.
So your chose is run it full factory, or shorten up the curve (and rework the springs when you do that or it will still be too much in the low mid range.).
Here's what the CAP vs non CAP timing curves look like for a '68.
cleaner air package
Some really good advice here, especially to check the timing from TDC and the entire curve.
Assuming the original factory distributor, it has 5* ATD as the spec because the primary advance curve is very fast and long. 0* TDC is 5 degrees more and that's about the limit of what you can add to initial if the fuel allowed it.
So your chose is run it full factory, or shorten up the curve (and rework the springs when you do that or it will still be too much in the low mid range.).
Here's what the CAP vs non CAP timing curves look like for a '68.
cleaner air package
