mufflers...tooo many choices! help!

hello, I'm baaack...

okay, here's the thing;
My stroked 390 is coming together really well right now (pumped up to 422 CI now...for the one who cares)
I have to do a break in at some time and was thinking of NOT doing that with just the headers...

So I already have a new problem of choice, before I have even finished the other job...

It's not a high revvin' screamer, but a torqy one (eh..torquey...torqueie...oh well, you get my drift, right?)

Anybody want to comment on what diameter exhaust pipes would bring me the best flow/performance and what kind of mufflers would get me the best out of this engine-setup?

It's hard, making a well thought out choice, not knowing the fundamentals behind each and every muffler out there on the market these days...