Hey guys, thanks for the information. We plan on keeping the rest of the exhaust stock. I noticed that the stainless 50 series Flowmasters have nearly the same size dimensions as the factory mufflers. So, that would make swapping them out easier.
I usually prefer the sound of chambered mufflers. However, this is on conventional pushrod V8s like my F150 and 5.0 Mustangs I have heard. I am going to run original 40 series on my 65 when it is drivable. I just didn't want my Dad's Cobra to be obnoxious and drive him nuts. That is why I was thinking about the 50 series.
I have heard several of the modular Cobra 4.6 with different exhaust setups. I just never knew what they were running for exhaust. I have heard a couple that sounded horrible though. One guy I talked to said that he had Magnaflow and no cats. His car did not sound good. I will try to listen to a few more and find out what they have on their cars at the local Saturday night cruise in / car show we have here.