I'm cleaning up a set of 140 heads I recently bought and the guides are shot (not a suprise). There is an incredible amount of carbon deposit on the inside of the intake ports (over 1/4" in some places) and the valve heads move radially about .010. Oddly, the valves are not worn - maybe there was a recent valve job. In any case, am I better off to have the guides replaced or to have them sleeved? Roger Gault