Another Lee's Speed Shop exclusive
Valve guides for Knucklehead, with a 5/16" stem diameter (rather than the stock 3/8") Available machined for a modern valve guide seal or as stock.
These precision guides come in your choice of either +.002” or +.006 over stock outer diameter. Material is cast iron. Nominal O. D. of the +.002 guide is .646" with a tolerance of plus .0002" to minus .0001". +.006 guide is .650 with same tolerances. The bore of the guides are .312" Slight honing of the guide will be required to achieve stock valve to guide clearances with most 5/16" stem valves. The O.D. of these guide can easily be sanded down for an easy custom fit to your head. These guides have been manufactured from the finest material exclusively for Lee's Speed Shop by Kibblewhite Precision Machining (of PM Black Diamond valve fame). Valve guide seals are manufactured by U.S.Seal Inc and replacements are readily available.