MuMu - First, yes the power steering fits with those headers no issues. Second, if you are going to use those headers, expect a performance limitation if you start wanting more power, those will be the bottle neck. Great headers, just not High Performance.
My learning - I have a 440 Dart, love it, is a front end heavy pig. With the 383 and your suspension upgrades, you should be fine for corning, etc, I would still look for some lightening mods - aluminum pump, housing, etc.
By looking at the picture, I don't see a pan, so that tells me you can see the internals. As with all dealings, I would think the seller will come down on the price a bit by simple negotiations. $3300 is not bad for all that, just what direction do you want to go. BTW, by the time you find and rebuild a 360 to make it a stroker, you will have $3300 and possibly then some for a full motor and exhaust.
And I like Jim Lusk's plan, if I did it over, how I would go. I would find a low cost 5.9, do the heads and injection and install. Upgrade everything around that.
And BoB - I agree