Cutlers Clutch tuning handbook is pretty good as well as AAEN racings clutch tuning handbook. I'll post the sites where you can purchase them. Both are good books to have if your going to be doing some tuning on your own. The timing key will advance your timing and give you alittle more power. depending on what fuel you are running you may need to upgrade to the next higher octane. You'll be doing this to prevent detonation. Also if the sled is an EFI it is not recommened to use the timing key.
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