reducing exhaust drone

I had delta flow 50's on my car and the drone was horrible. Changed to a different muffler to resolve.
Interesting. I have never cared for the flow master sound, though most I know use the 40 or 44 series. Been looking for someone who has the 50 or 70 series to see what they sound like for consideration on a future build.
Besides that, I have a (not very) used 50 here (single in, dual out) that I got for a song (very cheap) from a member here that I was thinking about putting on my /6 pick up. Because it's 3"in/out that has been adapted down to 2-1/2, I am thinking it won't "muffle" much being as how it's that much bigger than the exhaust ahead of and behind what this muffler is.
I also know that an inline 6 had a sound all it's own which is kind of "droney" from the get go compared to a V8....
I have the Thrush welded (their copy of a flow master) on my otherwise stock 318 in my Fury (still rocking lean burn even, at this time, it's "that" stock!) And it's slightly louder than I'd like-- not obnoxiously so though-- there's no drone. It has true duals all the way from manifolds to the bumper. Tails exit straight out under the bumper, not turned down.
Though as I sit here hunting and pecking this on my phone, I can't remember whether they ran 2&1/4 or 2&1/2" pipe, it's been on there over 10 years.
Though when I had my Diplomat, I had headers and "muffler shop turbos" on that one also true duals run all the way out, and that one was definitely 2-1/2 tube/ that exhaust was obnoxiously loud.

Then (another 318) when I had my 83 D250 and put headers on that one and true duals again with "muffler shop issue" turbos that one was definitely hearable but was nice and mellow..... Don't know what the difference might have been there?