When running a Mopar ignition box (orange, chrome, or gold) the box will pull out five degrees of advance at 4000 RPM and above. So the total timing is 42 degrees BTDC but once above 4000 RPM it drops to 37 degrees BTDC. This timing retard is not found in the Rev-n-ator ignition box, hence the reason the instructions for that box state to pull out 3-5 degrees of timing when initially setting timing with that box. Timing can then be tested/adjusted like normal for the best performance. This is an interesting tidbit I discovered after the article was written when I was graphing the timing curve.

Chris