Big block exhaust is still loud

I have a fresh 9:1 Ford 400 in my 75 F250, Gladys. It has 1 7/8 primary tube, 3" collector headers with 3" exhaust (with no cross over) to the rear axle with turn downs. I have the Summit welded, Flowmaster knockoffs on it. I was kinda worried it would be too loud, but much to my surprise, it's surprisingly quiet. I don't think there's any way I'd go back down to a 2 1/2" pipe. I can get a video if you like.