A 355 is just a 350 bored 0.030 over. There really is no difference.
this is true but to further the answer if only you bore the cylenders out in the block you will need to buy aftermarket pistons...
It depends on what you are going to do with them.
Pulling big loads are hauling alot, the big block is nice.
The small block is by far the best engine for all round use. It is cheaper to maintain...