Thanks Guys!
Looks like I've got my work cut out for me.
Am I right in thinking that if it is piston slap, it will get worse (louder) as I put more miles on it? Also, why don't I hear anything when it's cold?

Denny, FYI, it's got 76,000 miles on it and the previous owner says he rebuilt the engine. That's all I know but it just occured to me that if I've got that much play in the cylinders, why doesn't it smoke
and use oil??