Motor is a 1965 425. The motor was rebuilt in 2011, (prior to me owning the car), but the car has been driven less than 50 miles since. The motor sat unstarted for several years (during a frame off resto - the rocker arms were loosened during that time), then driven only intermittently since. Right after the rebuild, the motor was quiet. The motor runs fine, but there appears to be what is a pretty loud lifter tick on #6. There is oil coming up the pushrods and the rockers all look to have the same amount of oil on them. The rockers do not show any abnormal wear and there is no play when on the base circle. I just changed the oil and filter and added a quart of Rislone. I cut open the filter and there was no metal visible. I have only driven it a few miles since the oil change. Short of pulling the intake and changing out the lifters, are there any other suggestions to get it to quiet down?

 

If it's not loud enough to the point you think there will be damage, let the Rislone do its thing and then change the oil and filter.