If you have the money- its the single easiest way to make much more torque (and increase your HP a bit too

)
Scat or Eagle cranks seem to be the best out there, you can get kits directly from them - or from DSS, Coast High Performance, or Ford Performance solutions.
Or you could work with an engine shop near you that you trust to get the parts.
I'm building an EFI 315W right now and am debating the ~356(0.030 overbore stock) vs. 393/408/418. I would like the 418, but its all $$ and its tight. With a 393 you just need a custom crank and some clearancing (~$400 upgrade), stock rods and pistons will work. With the 408 you need custom pistons and crank (~$600 upgrade), and 418 you need custom pistons and chevy rods (~$800 upgrade). You can also go full out and go for a 427 if your block is healthy
Some other things to consider
- will the block you have be able to take the extra stroke? - if its a post '74 block (non-SVO) with the thinner main webs, you may not want to go over 393-408 (assuming your going to use it hard too).
- Will your heads and intake support the stroker? If your running stock, unported heads - you may be semi-wasting your time building a stroker if you want mid-high end power too, so you may want some porting and polishing done on your heads and intake to increase the flow of them, or get some aftermarket components.
- will the rest of your components down the line be able to take the power? For me, I would need to be very careful with the throttle or break down and get a new output shaft or the Atlas if I were to go much bigger than stock as I don't trust the EB Dana 20 with that much HP and torque.