Frank thomas

Wanting to install a LS engine, the 4.3 just isn't enough. Looking for 300 HP and keeping my trans if possible. Was told new 6 speed out of camera would not go without cutting up floorboard. Trying to find out what to buy, what Accessories, oil pan, etc needed to do swap. Like to have all alum engine due to keeping weight same or less.
Any guidance would be greatly appreciated. Thanks Frank. 803-523-4806.