How much to stroke a windsor?

That will cost you a pocket full. All new equiptment is the pisser there. Most stroker kits start out at about $950-$1,000 depending on who you buy from and what you get..Machine shops can do that kind of work pretty easily as most on here will tell you. If you can get a windsor cheap then go for it.
 
I was quoted

over $6,000.

I declined. This was for a forged SCAT 396 stroker kit (including a healthy mark up on the engine shop's behalf as well), and new just about everything else (heads, cam, radiator, carb, etc) and the labor to pull the engine, dissassemble it, reassemble, final tune, etc. In the end, I opted for the work you see below in my sig. It would have been an extra $2.5k for the stroke compared to what I actually did but I ended up with 360 rwhp, which means a lot more than that at the fly. I can live with what I have. For now.
 
The kit alone will cost in the realm of $900-$3000 depending on how fancy you want to get. Plan on No less than $400-$500 for machine work to the block and balancing the kit. Then you will need rings, bearings, cam bearings, freeze plugs, flexplate, dampner, headers, etc. It gets pricey real quick.