Seller notes

The S&S KN421 cam is intended for large displacement Knucklehead engines such as the 103" Flathead Power KN-Series produced engines.With a .420 valve lift, just like the S&S KN420 cam, the KN421 cam has yet a longer duration for engines larger than 93" and compression ratio of 8.5:1 or higher.Special high-lift valve springs are required (as offered for Knucklehead by S&S and Leineweber)This cam is designed to be used with solid lifters.This is a great whole range Knuckle cam. Make sure that you ...

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