383 commando ..whats it worth?

A short block has no heads. A long block has heads and no intake. If I was you I would look around some more. Don't get stuck on "Commando", it it just a term for a performance build. You can do alot with $800 toward an engine that will outperform a "Commando". Look for the code HP on fender tags at a rural salvage yard to get your core and go from there.