[Mr. P-Body]

If you are, or have access to, an electronics guru and a fabricator, it wouldn't be TOO difficult. You'll need all the correct electronics to make the fuel and spark systems work. There is no provision in LS1 for a distributor, and no intakes for carbs. The intake could be fabricated with little problem. I suppose you could adapt a crank trigger system.
Now for the $64 question: "Why?" A 400 makes more power and is cheaper to build (LS1 is no bargain!). I would guess fuel efficiency and weight are the rationale?
Don't misunderstand. I REALLY like LS1. Cool engine! But it's no Pontiac when it comes to power output, at least at the milder levels. In a heavy car, I would think it a bit shy on torque.