I am looking for recommendations for loud slip-ons?

Thinking Thunderheader?

 

They will be loud.
So will almost any aftermarket slip ons, except for Screamin Eagles. And some offer different size baffles to make them even louder.
Think Pythons, Rush, Cycle Shack, Full Boar and Rineharts, just to name a few.
What bike are you putting them on?

 

Kerker/Supertrapp with the PAT baffles.

 

Screaming Eagle slipons will be loud too if you remove the baffles and replace them with thunder torque inserts.

 

Thunder header slip ons are very loud, and sound pretty good...they aren't your 5am neighbor friendly listen to some in person, or there are a couple good you tube videos using thunder header thunder cones

edit: using them on my 110, i had to bend 3 tabs on each to get a little low end, while running true duals

 

V&H Straightshots. Not ungodly loud, but close.

 

My V&H give me a headache. I'm looking for something else.

 

Cobra 3" Slash Cut Slip Ons. They are not quite as loud or harsh as the V&H Straightshots I had on my Sportster 48, but they are still pretty great. You can also rotate the end caps on them in case you want a slash cut, bologna cut, etc. I use them on my Slim and I love them.

 

This is on an M8 SG with stock headpipe with cat. Stock intake and stock tune. Turn up the volume.

 

Nice, that works for me. Appreciate the post.