Bummer man. Unfortunately, I'm about 95% sure you won't be able to just put another piston in it and go. When the ring lands go, they tend to take the cylinder bore with them. You might get lucky. Or, you might be able to get a sleeved block that will allow you to use the stock pistons.
Either way, I feel your pain. These 5.0s are real fun right up til they get punched in the glass jaw.
