Double check your push rod length, the intake and exhaust push rods are different lengths you may have the wrong length one and if the engine is at bottom dead center of cyl 1 the cam lobe will be all the way down making the lifter as low as it gets.
Answers & Comments
Double check your push rod length, the intake and exhaust push rods are different lengths you may have the wrong length one and if the engine is at bottom dead center of cyl 1 the cam lobe will be all the way down making the lifter as low as it gets.
Lifter failure
Collapsed lifter and or worn cam lobe .
https://www.youtube.com/watch?v=21swnCbDCKk