It will sound good in my opinion...I'm in the minority here that like Flowmasters. Contrary to what you see on the internet, you'll likely not lose any power w/ them considering how mild your build is.
If they are 40 series, that's a 2 chamber. It'll definitely be noticeable, but not crazy loud.
Here's my hemi w/ 4" single chamber Flowmasters. It's definitely a lot louder than yours will be.
https://www.youtube.com/watch?v=FmOtBb4oaY8FWIW...my old combo of a 509/292 cam, ported iron heads, 440 that ran 11.40s at 117 mph in my cuda was with 3" exhaust and 40 series flowmasters. It ran the same with or w/o the exhaust on it.
