The plastic keys in the kit are numbered in even degrees starting with 14 and ending at 28. The distributor I have been using was already limited to 14 degrees by this same method. I read the instructions included in the Mallory tuning kit and used the stiffest springs that were included. This resulted in the advance starting about 350 rpms AFTER idle instead of immediately after. This was a step in the right direction, but the 14 degrees of timing was still all in by 2350 to 2400. This is why I mentioned that Maybe I need stiffer springs to S L O W the curve even more. The Mallory kit brown and orange springs are the the thickest and firmest in there. The weights are rather light though.