Will a 1988 350 Chevrolet engine work in a 1995 Chevrolet Silverado.?

My dad has a 1995 Chevy Silverado and it has an egg shaped piston and it burns oil, its a throttle body and he found a engine that has a carburetor on it. Will it fit in his truck or would he have to get something done. If you could help me that would be great.. Thanks..