I bought my '65 dart as as roller, so I have no reference. I'd prefer to run factory routed exhaust system with my 365 HP 273 and not modify the drivers tranny mount. Probably a 2 1/2 pipe. Seeing the route is better for me to see what's in store. Thanks
EXHAUST SYSTEM PICS
- Thread starter A/MP
- Start date
-
☆☆☆☆☆
235 horse 273? The early cars only have a trans cutout on the driver's side only. For any proper dual exhaust you will need to modify the crossmember.
Last edited:
JDMopar
Well-Known Member
A 65 Dart with a 273 four barrel motor would have had a single exhaust pipe down the drivers side of the driveshaft tunnel, in the factory configuration. If you try to run that with stock manifolds on a 273 that's making 365 HP, it will choke it to death. There are several threads and pics here on the modification that needs to be done to the passenger side of the torsion bar crossmember and transmission mount crossmember to keep that side exhaust pipe from hanging so low. I'm going to do the mods to my 65 Barracuda for the warmed up 273 going into it, to get true dual exhaust. My motor is going to the dyno soon, and I will faint and fall over if it makes 365 HP....lol. I know mine won't make that much, but it will be enough to benefit from true duals. A bigger single exhaust like factory was fine for 235 HP. If you truly have 130 more HP coming out of a 273......you need better exhaust to take advantage of it.
There's a picture here. The Accurite system is nice but not cheap. I didn't have a hoist so I didn't get any photos. 1965-67 273 Hi-po System for Barracuda & Dart
Professor Fate
Push the button, Max...
First off, if you're pushing 365 hp out of a 273, I'll have to assume that you're running headers; most likely the Doug's D450s or TTi 636A. I'd be truly shocked if you generate those numbers through the factory exhaust manifolds.
Look at where the collectors end- almost right up to the crossmember. If you refuse to notch the crossmember, you'd have to run a 90 immediately out of one collector, and drop it down under the transmission to connect with the other side. Really poor ground clearance. (The factory crossed over in front of the transmission, but that was with manifolds. Headers extend way beyond that point.)
And then you want to take both of those 2 1/2 or 3" collectors (depending on brand) and funnel them both into a single 2 1/2 pipe and muffler? A lower horsepower motor would perform just as well through a system like that, you could have saved yourself quite a bit of coin on the engine build if your intent was to just choke it back down to a lower power level anyway... The 235 horse motor did fine with the single (it honestly is a really nice system), but even the 275 hp D-Darts came with headers. And you've got 365...?
Reconsider notching the crossmember- I'd be surprised if it takes all of a half hour to do. If you don't feel comfortable doing it, TTi can do it for you:
https://ttiexhaust.com/Sheets/Crossmember_sheet506.pdf . I heard Layson's can do it, too.
Look at where the collectors end- almost right up to the crossmember. If you refuse to notch the crossmember, you'd have to run a 90 immediately out of one collector, and drop it down under the transmission to connect with the other side. Really poor ground clearance. (The factory crossed over in front of the transmission, but that was with manifolds. Headers extend way beyond that point.)
And then you want to take both of those 2 1/2 or 3" collectors (depending on brand) and funnel them both into a single 2 1/2 pipe and muffler? A lower horsepower motor would perform just as well through a system like that, you could have saved yourself quite a bit of coin on the engine build if your intent was to just choke it back down to a lower power level anyway... The 235 horse motor did fine with the single (it honestly is a really nice system), but even the 275 hp D-Darts came with headers. And you've got 365...?
Reconsider notching the crossmember- I'd be surprised if it takes all of a half hour to do. If you don't feel comfortable doing it, TTi can do it for you:
https://ttiexhaust.com/Sheets/Crossmember_sheet506.pdf . I heard Layson's can do it, too.
365. I need to see the dyno sheets on that one. A warmed over 340 on another thread didn't come close to that.
That will be one NASTACIOUS 273. So much so, it would have limited streetability.
You need to treat the 273 like a 283. If you know the original history of the 273/4, it bested all the sb until the 283/4 showed up. There is a reason that TRW made a .070 high top piston or the 273. It will take a .060 without any problems provided the core checks out. Then its the heads and very good machine work. There's plenty of power to be made. Its just not going to last as a daily driver.
-
