The '56 would at least be a full pressure oiler which is good. If it's from a car with the cast iron powerglide it'll have hydraulic valve lifters, not solids. If it has the "848" cylinder head the stock compression will be a little higher too.
You can do lots of internal mods to increase power some, but don't expect any huge increase. There's an old Hot Rod mag article from '55 I think,that explains a lot to be do e. Just depends on what you want to spend.
