This became apparent after I did the Deckplate and put in the Amsoil filter.
Its a "whistle-howl" that happens when the engine is under load at 2-3k RPM. After it shifts into the next gear (RPM drops) it'll give almost a blowoff sound.

With the deckplate in place it is less noticable but still present.

With the deckplate off and paper filter its almost totally gone.

With paper/deckplate on its pretty much gone. But if I really really listen I can kinda catch a hint sorta maybe.

I double checked all the vacume lines after the install just to be sure.

I knew there would be more intake noise after the deckplate but it seems like its the filter that makes the most difference.

My truck has almost 115k so I'm kinda thinking it may be a clogged Cat (meow).

Any other "deckplaters" have this noise?

 

Maybe I should have a woman post this