The Stovebolt Site Forums The Shop Area Engine Shop Bad engine noise - video.

I can't remember when I had my 283 torn down if there is a threaded 7/16" bolt hole inline with the fuel pump rod, I know on the 350's that hole goes through to the rod cavity and if you install a bolt that is too long it will pinch the rod. I wonder if a bolt is in that hole that is just slightly binding the pump rod and not allowing it to follow the cam, especially with the softer spring in that particular pump.