I would Ls swap it using a 5.3 truck motor. I've already decided that's what I will be doing if something should ever happen to mine. The exhaust manifolds are readily available online and 5.3's are a dime a dozen. With the right camshaft you can see around 400 hp. But if you don't have tuning capabilities of the engine or the means to make an engine harness, I'd say forget it and go with what came from the factory.