I did work with that a little. I have an HEI and I took it apart, cleaned it up and installed the lightest springs that came with the accel type kit. There were 3 types of springs. The vacuum advance works. Have it set at 10 btdc at idle, and it is all in around 2800 at 36 degrees. I have played with it, but it has been A long time since I really set up a HEI dist or timing for that matter. Do you think I should use a vacuum guage? Give me your input on how to correctly set up the timing if you don't mind.