The 65-67 hi-po exhaust systems always included a muffler coupled with the resonator/tip unit. The early 65 exhaust systems had a straight through style muffler that was replaced later in the year because of noise abatement concerns. The "Magnum" style muffler from Accurate LTD is the straight through
design and works great for a more aggressive exhaust note. Because of this design it will display resonation at certain speeds and loads.
