I thought I could get the pump off without pulling the head? Just those two front bolts that hold the head to the cover? No? I had planned on pulling the pans and checking out the rod bearings and main bearings.

I have to confess I don't know what chain slap or piston slap sounds like. My CA's had spun bearings before, and I assumed that was what I was hearing. I guess I should get someone who knows a little more to come listen before I pull it apart... Its pretty loud, I mean people could hear me pulling in the driveway from inside the house.

This is almost exactly what it sounds like. And you have to give it a little throttle like they're doing to hear the noise. One of the comment suggests its piston slap too...

http://www.youtube.com/watch?v=uZplzqSbKmo