Hi Krazed. Sounds like a nice car you have. It's great you found your car's "birth certificate"!
I know that you have a 340 but a blurb on Allpar talks of the Formula S option with the 383 engine. Here it is and the page it's from: Plymouth cars of 1968.
"A required option on all 383-equipped Barracudas was the Formula S package. It featured bigger torsion bars, a front sway bar, heavy duty shocks, six-leaf rear springs, 5.5x14 wheels with wide oval fires, ten-inch brakes and, of course, round front fender medallions. Disk brakes, also a required option with the 383, were available on all Barracudas, the standard Barracuda engine was the 225 Slant Six. A 273 two-barrel was the standard V8."
http://www.allpar.com/history/plymouth/plymouths-1968.htmlIt doesn't state that Formula S package came with dual exhaust. It may be engine dependent. On this page they mention how the 273 V8 didn't come with duals because it was a carry over from the previous model Barracuda which had no space for duals. It also states that 383 Barracudas had duals. Sorry, I know, no definate answer, but your 340 is somewhere in between.
Hope this gave you a little info!
