1996 Chevrolet Cavi

LOTS. You're talking about a major part of a total engine rebuild. Pistons aren't just slapped in. They must be installed very carefully with special tools that won't scratch them or the cylinder. The cylinder head must be removed to get the old piston out and the new one in. Typically just one isn't replaced. You normally do all four or six, ( you didn't bother to list the engine size or mileage). When you get that involved, you might as well rebuild the entire engine. To just do a repair of that magnitude would be like wearing all new clothes except for one dirty sock.