fe tapping any ideas

I finally got the electric fuel pump hooked up on my truck. I went to drive it and heard a tap at about 2500 rpm. It hols good oil pressure and does not tap until about 2500 rpm. My dad told me it might be a loose rocker arm. I checked and all were torqued to 45lb. I am thinking possibly a bad lifter. It does not sound like a rod knock. Anybody else have any ideas

 

The stock fuel pump on an FE can do that, along with all eight of the wrist pin bushings. Piston slap. Use motor oil meant for a diesel and drive it like you stole it.

 

I have an electric pump on it and have the mounting source blocked off. I am running 20w50 oil in it