Exhaust system for a 1965 Dodge Dart GT
I have complete TTI system in my 65 dart - headers and 2.5 dual exhaust with crossover and dynomax Super Turbo mufflers. Nice system, but not without issues. I think it is quite loud even at idle and cruising. Some people would probably like it, but it gives me a headache after a few minutes. I'm hoping to add resonators soon. I also have little to no clearance between the headers and the torsion bar on the passenger side. I actually get some noise, clanging and rubbing at idle in reverse. I have 0.83" torsion bars, so no room for larger diameter bars either.
Interesting. Passenger side no problem on my 65 Barracuda's TTI's, but I had near zero clearance between the torsion bar and the two tubes it ran between on the driver's side. Fixed that with a later A body motor mount biscuit on that side (keeping the original 273 bracket), which wasn't as tall as the original 273. Dropped the motor just enough to give me clearance, no rattles. I have .89 torsion bars.
On the passenger side, you may need to put a spacer under the biscuit to raise the motor up a bit. This assumes, of course, that you have a 273 biscuit in there now. If not, may need to switch to it.
To get back to the original OP, TTI headers will give you the best power, but they are a tight fit in that small engine compartment, and I could write a short story of all the things I had to move (brake and electrical lines mostly) to get everything to clear. I agree, though, with Cudamark that your bottleneck is the 273 manifolds, not the rest of the exhaust. There are options, including 340 manifolds (very expensive these days), Spitfire headers or OEM Magnum manifolds. All this has been discussed many times, so I won't try to go in depth here.
At this point, if you're keeping the 273 manifolds, I agree with those who say go with the factory 273 hi-po big single exhaust. For whatever my opinion is worth. :realcrazy: