OK, Halifax, so what should i do in my situation? I know 18 initial works nice and from reading a lot of cammed up engines, it will probably like somewhere between 34-36 total..SO, should i just ad a second lightweight spring to slow down the advance or? Also, i am interested in trying the vacuum advance but im afraid that when i am at a cruise and the vacuum advance is working it most and that split second when i tromp down on it, im afraid it will ping that split second it takes for the vacuum to drop off and release the vacuum advance..Wish i could pay you to put this thing on your distributor machine and set it up how it needs to be..