ED xr6 project.

I'm wanting to start working on my ED and this is where I will be asking any questions I have.
...Which will be a lot...
My aim is 400 rwkw.
I plan to spend a few years on this as I want to boost it and it will be a while before I'm off my p plates.
To start with, I'm going to buy another engine (so I can still drive it for the moment) and stick it on a stand and build that.
I'm wondering which block would be the best to start with, which ones will fit, or if there's one that is simply the best, I'd like to know about it!
...Which will be a lot...
My aim is 400 rwkw.
I plan to spend a few years on this as I want to boost it and it will be a while before I'm off my p plates.
To start with, I'm going to buy another engine (so I can still drive it for the moment) and stick it on a stand and build that.
I'm wondering which block would be the best to start with, which ones will fit, or if there's one that is simply the best, I'd like to know about it!