indirect_connection
Well-Known Member
Looking to add a Summit or Jegs Dual exhaust kit to my 1968 Dart. Has anyone ever fabbed their own headpipes? I know TTI makes them, but at that price I might as well get headers.
Dual Exhaust with 318 Manifolds
- Thread starter indirect_connection
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65Val
Average Length Member
Had the muffler shop fab mine...was about $150, I think.
indirect_connection
Well-Known Member
Did they use 2.5 inch all the way to the manifold or start with smaller pipe and adapt to the larger?
You can’t do a 2-1/2 to the manifold. You have to start at the exhaust manifolds exhaust size (or maximum size) and work up in diameter from there. Actual size will vary due to exhaust manifold differences.
I believe the opening on the stock 318 manifolds is 1 7/8". You can put 2" pipe at the manifold, but that's as large as will fit. From there, you have to come out and adapt up to whatever size you want. I'd just run the 1 7/8" off the manifold and then increase the size. The difference between the 1 7/8 and 2" right off the manifold will never, ever be noticed. If you want 2.5" then you need some 340 manifolds or headers.
indirect_connection
Well-Known Member
Makes sense. I only asked because TTI advertises their’s as 2.5.
I've used the TTI head pipes on both my Dusters. Fit like a glove. 2.5 mandrel bent.
I think that’s the best bet really.
If your exhaust guy can cab up something good for a cheaper price....
Nice thing about the TTI's, is they go down to the cross member, so it's pretty easy to go 2.5 duals from there back
j par
Well-hung Member
"IF" you have horsepower aspirations and possible header aspirations for the future think about the size of pipe you'll want then and if you want to repipe the whole thing again for it...
indirect_connection
Well-Known Member
I haven’t decided on future engine choices, but this car will stay a cruiser. Tti is sounding like they may be worth the extra money to get the mandrel bends.
It is pressing the EZ button. The parts are normally very good quality. Hard to say no sometimes. You’ll forget the price long down the road.
Just installed TTI head pipes and Jegs exhaust on my build. But I went out the side with mine. Starts on about post number 292. Good quality on both. Very happy.
1974 Scamp some assembly required
indirect_connection
Well-Known Member
Well that’s good to know. I ordered the Jegs 2.5 kit with the turbo mufflers earlier today.
Slantsix64
Well-Known Member
Get the 73 340 driver side manifold 2.25 outlet (if you have power steering) and dakota passenger side 2 1/8 exit, if you dont have power steering and it is an automatic you can use both dakota manifolds. stock LA 318 manifolds are weak flowing, Headers are cool but wayyy to much for decent ones.
MopaR&D
Nerd Member
I'd run some shop-made compression-bent 2" pipes a few feet off the stock manifolds, you're going to lose low-end and mid-range torque putting 2.5" pipes on manifolds with 1 7/8" outlets. Has the same effect as basically running with open manifolds, there's no exhaust gas velocity at lower RPMs. And having the stock manifolds will restrict breathing at higher revs anyway, might as well try to get the most torque across the whole rev range.
Also IMO mandrel bends won't do diddly with that kind of setup, pipes will be too big anyway. Now if you were running headers it would be a different story.
Also IMO mandrel bends won't do diddly with that kind of setup, pipes will be too big anyway. Now if you were running headers it would be a different story.
j par
Well-hung Member
"do diddly"... LOL...
Does it fit on the 1 7/8 opening? Splain that please.
yep, obviously the 1 7/8 is the size of the ball socket, then into 2.5
Oh ok. Gotchya. I thought maybe there was some alien voodoo goin on.Thanks.
LOL... if the OP would like to see a picture, I can easily take a picture as I have installed Doug's on one of my Dusters, so the manifolds and TTI head pipes are laying in my basement
indirect_connection
Well-Known Member
The OP would like a picture, and possibly for you to sell him your unused headpipes..
Here is what I had on my Duster. Head pipes from TTI are manifold # specific (style). Mind you, they were on a '76 Duster. I have the exact same manifolds and TTI head pipes on my '74 Duster
indirect_connection
Well-Known Member
Yes, the driver's side manifold is definitely different than mine.
Drivers side in the picture is from a B/E body small block, obviously '73. I actually had power steering on my car and had to "notch" the original pipe where the bolt connects to the pipe flange to manifold. Nothing to it. I went to manual steering and also went to the TTI's at the same time. Obviously, with manual steering I had almost an inch clearing.
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