Or a worn cylinder bore.... or a bent rod... or rod small end bearing wear from inadequate lubrication.... broken, stuck or worn piston rings.... or a combination of things. As Eddy said, a rebuild is the only answer.

Here's one way to diagnose piston slap:

Test for Piston Slap

Frank

'89 [color:"white"]G-Raider[color:"white"] [color:"black"]Supercharged 3.0L, MegaSquirt 2, lockup A/T, 2.5" exhaust, 172k, Cibie H4s/Oscar SCs, Hella Micro DE fogs, Cobra CB, Superwinch hubs, LSD rear/Aussie Locker front, Bilsteins, Lifeline AGM, Rust-Oleum