there is an overwhelming amount of info on this mod, but I can't seem to find what it actually does for you, I have gathered that plus 4 timing is good and easy to do, but why is it good? I just bought my shee, it has a cool head with unknown dome size, guy said 22 or 21, so with the timing mod can get smaller domes and still run pump gas? Or is there gains to be had just by changing the timing and nothing else?