LT1 vs. Vortec vs. LSx

[kevinr1970]

So in my '82 K5 2wd I am planning a slightly more modern drivetrain.

I am not sure I want to go the LSx route as I want to keep costs low(er) and already have sbc headers, engine mounts, etc.

My orginal thought was to get a Vortec 5.7/4l60e out of a '96-00 truck ('03 for vans?). I have seen a few 2wd trucks with hi-miles come up in the $1000 range, figuring I would rebuild the engine/tranny.
But I have seen a few '93-96 Caprice/Roadmaster/Impalas come up in the same price range, same condition. Even saw a Trans-Am needing an engine rebuild for under $1000.

I am going to keep it FI, not interested in going back to carb.
Not going radical on it, just a good stock FI sbc.
Not interested in a 6.0 due to fuel mileage.

What are the pluses and minuses of either engine combo?