You need to set a goal hp wise and build around that . Seem to be all over on what to use. A stroker stock block windsor with the right stuff will make real healthy power for a street car. I have a friend on a 79 351 block thats .030 over (357) that just went 8.92 a few months ago single turbo, victor juniors, gt40 with a box upper and a pms with a power glide-Nothing special there.
If your going to do a 400 inch type build id get yourself a set of afr or tfs 205cc heads. Call Brian Freezy, Ed curtis , Buddy Rawls, or Bullet for custom cam.
Also before the cam choice and head choice is made you need to decide if this engine is gonna be a 10.5:1-11:1 pump gas motor all motor or if your gonna run a power adder like a blower or turbo and build for low compression.This way you can get the correct head, head gasket, piston, and then cam spec'd accordingly. Get a good intake manifold- systemax is a good one, The spider efi is nice as well. If its doable id use long tubes. My car is low. I have 1 3/4 long tubes and they still haven't touched the ground.
Another thing to plan around is emissions laws in your state. Exhaust , cam, and other stuff could be affected by this. Saying that the car is a v6 swap car i doubt its an issue in your state but just thought id bring it up.
As far as the trans A astro may hold up for you but personally id buy a tko 600 for the car over the t5 based trans. Make sure the rear is up to snuff with at least 31 spline axles.
We still haven't touched on a fuel system either-Injectors,Lines, Regulator, Rails, and pump. (Again the fuel sysetm needs to be specd around how much power you want to make). Then you'll need something to tune the car with to get it to drive like a street car should and make the power efficiently . My advice is to plan , Buy once, Dont cheap out. Youll thank youself in the long run.
@84Ttop has a gangster windsor street car. Maybe he can give some advice or touch on something i missed.