This and maybe some resonator tips if you want to tone it down a bit.

I had Flowmaster 40's on my 1967 Camaro. To me they were too loud both outside and inside the car. I replaced them with Magnaflow 11226 and it really made a difference.

If thats what you have the cheapest way is to move the mufflers back and add tail pipes and a crossover tube as well. Otherwise if you are mechanically inclined there are a number of kits as well .Good luck to you.

Hello there
the exhaust on my 68 was leaking as no heat riser was installed. I guess I have some parts missing, can I get somewhere a drawing showing both sides and what gaskets, donut and sleeves are required?
I had a sleeve and donut on the left and nothing on the right. Flange bolted directly on the manifold...

Had the Open Chamber exhaust and didn't like sound. Switched to Magnaflows and I really like tone. Sound is very mellow with some rumble. Engine is 350 with stock cam and headers. Nothing too radical. Our car is just a cruiser.

I had FM 40's with my stock 327. My new 355 H/C motor with headers exhaust was annoying loud so I just put on FlowMaster FX mufflers. They are not chambered. They are straight through like MagnaFlo and Dynomax mufflers. Nice lower tone sound but they do light up at WOT. Stainless steel welded. $41 each