If you know the bottem end is solid, just get new headgaskets and intake gasket. Would be a good time for a new rear main and oil pan gasket aswell.

And if you wanted just a straight swap with no other modding, you need to buy a L67 or L32 short block (those are supercharged). If you bought a NA bottem end you would have to do extra stuff, and its not worth the time.