help with 273

Ok, I put together a 318 out of a 75 lebaron wagon. Compression is stock. Heads are mildly ported, valves are back cut at 30 degrees. I have a comp cam 268 magnum muscle kit (cam, lifters, springs, locks, seals, timing set) air gap intake, holley 600 cfm 4bbl. I think the cam is like 268/272 and lift of .464 or somethin. Anyway, for now I put it in front of the 3 speed. Since I did that, I had to use the 273 manifolds as there is no way a header is goin in on that side. I plan to eventually get an auto trans built for it and switch over to headers. In the mean time, what exhaust set up will sound good on my 318 with manifolds? I would like to have a deep throaty rumble to it. I was thinkin duals into flowmasters and then dump down right off the mufflers hopefully in front of the rear axle. Any thoughts or ideas? I have the 273 y pipe to work off of (or cut and run trrue duals) Ides? Lets hear em!