Visual clues are good enuf...look at the bottom of the lifters. If they are scrubbed off, the cam and lifters are bad. This will normally be reflected by the cam lobes which will look funny as well on the lobes affected.
When the lifters are new, they are slightly convex on the bottom. If you set them on a piece of plate glass (plate glass is normally very flat), then they should rock a little rather than sitting perfectly square to the glass.
Nothing wrong with flat tappet cams. Most failures are due to user error on break end and/or cheap chinese lifters which are not hardened. These days lifters are being made in this country but the trick is in knowing if the set you buy is US made, or not. An used cam is generally the safest cam to install if the lifters go back on the original lobes.
It is strange that one hears about the dangers of flat tappet cams but, one seldom sees an actual case of a failure from real engine builders.
Just remember that a lifter has to go back on the lobe it came off. You cannot shuffle used lifters around on different lobes. Instant disaster!!!!!!!!!!!!
great info as always. I haven't taken the lifters out yet, I did make sure the keep the pushrods in the correct order.
