Chevrolet Repair: chevy 7.4 fleetwood flair 1992 tappets, tappets, hook up

Question
1xcam follower becomes noisy after holding revs at 3500rpm for about 3 mins.
i ve changed oil and filter with a flushing agent but still doing it can you help
thanx JUSTIN uk

Answer
I would not hold the rpm that high for a long period.  It is not a good idea, especially if the motor is old.  

At idle, hook up a vacuum guage.  Is this telling you anything?  If you have steady 14", then valves are ok.  If you get a jumpy needle, then you can suspect the follower of being faulty.  

Cruising speed is usually 1800 - 2200 rpm.  5000 is danger zone of redline.  I would not hold the idle that high for fear of spinning a bearing or hurting something else.