Starting my parts gathering

So I have a complete 318 engine and I am begining to gather and research parts for a small block build. I have read and heard that a 273 crank would be a good choice as they are forged and the same stroke and main journal size. I am not wanting or needing to stroke this thing out!
I have a lock on a 273 crank and rods for basically free, out of a running motor! Free is always good.

My current engine in the fish is a 273! So my plan is to have the 318 block gone through and over bored .030 over, using the 273 crank and rods. So what are good pistons? I will either be using stock 318 heads with mild porting or Edelbrock performer aluminum heads, if I can justify to the wife the expense!!!

I want as much horse power as I can get but really reliability is also a big factor. I think with the right cam and head work,intake and carb I can get 400 hp. Is that possible? not looking for a strip machine, just a Honda killer and street cruiser!

Thanks,
John B.