Pequa - you sure that Dust 340 had a 6-pack in it? Because the Duster was never offered with that intake setup. The 'Cuda had it in the AAR version. Maybe your friend added it? Had to be an expensive conversion, even back in the day. I know this stuff because after I sold my Charger (BIG mistake) my next ride was a '71 Duster 340. That was the last year of the Mopar hi-compression engines, and that car (at a ridiculously underrated 275 hp) used to eat 350/350 Novas for lunch, it could even hold its own against 396 Novas and Chevelles - which were quite popular, back in the day.
At the '70 NY car show I asked the Mopar guys why the Chevy 350 was rated at 350hp, while the MOPAR 340 was so comparatively low on hp. They look at each other and laughed a little, then told me that motor was purposely underrated, as the insurance companies had been targeting MOPAR owners with ridiculously high premiums, based on engine hp. They said that engine was actually outputting in the 350-360hp range. Add headers and some carburation tweaking and it was truly a fast little ride. By '72 it was all over - MOPAR had to cut the compression in all their performance engines (GM did that in '71), and that was when true high-perf American engines went away.
Quick story about my Duster 340. That car was kind of bare-bones, with a bench seat up front, and a factory floor-mounted Hurst "pistol grip" shifter in the floor. With the 4.10 gears that we put in it, I would launch HARD! Not to mention that my "One-Two" upshift was so strong that I actually put a deep dent in the seat where the shifter (and my hand) would hit it. One late night on 231 in Babylon I was racing a Mustang Mach 1 just south of the SS Parkway light. I pulled second so hard that I yanked the shifter right out of the floor. Race over, he won. I still had 2nd gear, but that was it, couldn't up or down shift. Had to drive home to Plainedge from Babylon at less than 20mph, straight down Sunrise Hwy. What a nite that was.
So next day I got under her and saw that the way Plymouth mounted the Hurst shifter to the transmission had an aluminum adapter plate between the shifter body and the box, and that was what cracked. So I went to my local Plymouth dealer for a replacement and of course no dice, none in stock. And because it was around the holidays the MOPAR warehouse was closed - no shipping until after Jan.1 - a solid week away.
What to do? So I hitched a ride to my job in Bay Shore - my boss lived in Bethpage and took me in with him. After I explained the problem, first he called me an idiot for messing around with hot rods to begin with, then he asked if I had tried SK Speed in Farmingdale, or the Mars Store in Bay Shore - both having a good supply of hot rod stuff. I called SK and that was a strike-out. At lunch we took a ride into Bayshore town to the Mars store - and damn, they had a box of the MOPAR shifter adapter plates in stock. Who would have thought? I got her back together that next day, and was a lot more careful with that 1-2 shift for the rest of the time I owned that car.
