Help me find the umph in my 360

The engine when I got it still had hydraulic flat tappet and stamped rockers. So I just went with another flat tappet. But I started the engine back up and it didn't make the noise until it got warm again. It definitely sounds deep. This sucks.
well hopefully nothing serious... just a few hours to pull it apart and find out.. if it's dead feel free to send me the block :)