Who Makes The Most Quiet Muffler for 68 340 GTS
Whatever muffler you choose, adding a Dr. Gas X-pipe
will knock off a few more decibels by evening-out the exhaust pulses.
(Otherwise, each tailpipe is like a totally separate 4-cylinder motor.)
In a test of 5 brands of X-pipes, the Dr Gas unit was far & away #1.
HTH----------------------8)
PS---If you insist on an OEM-level muffler, at least
insist on the Walker brand. You'll be glad you did.