Jeep 4.0 in 69 Barracuda

I had found a CFM chart on exhaust sizes. And as I recall a 2.5 in exhaust pipe has a 510ish cfm rate. 2in pipe has around 300cfm. So I am hoping the dual 2in pipes on a 2.5in single exhaust system will flow nicely and still sound good. Worst case, I cut it out and go full single. But I am willing to gamble. I found a youtube video of a cherokee with dual exhaust flowmaster, it sounds good to me. I think I will be happy with it.