Real talk: exhaust manifolds on 360 Dart

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Woodsman341

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Hi all,

(Editing to add: car is a '75 Dart 360 Sport)

I just found two good sets of stock exhaust manifolds for my 360 (current headers are abominable and since I'm building a street/daily driver type, I don't know if putting $1,000 into TTIs is the best route), and a good price. I'm wondering if there's any real world difference between a mildly built 360 using stock 360 exhaust manifolds versus using a set of 340 HP manifolds.

Thanks!
 
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In an A body? I don’t think there are any 360 manifolds (driver side) that fit an a body. That being said, I bet the 340 hp manifolds would show +- 10 hp on a mild 360 over the 360 manifolds, and both would be down 15-30hp on a good set of headers.
 
TT5.9mag said:
In an A body? I don’t think there are any 360 manifolds (driver side) that fit an a body. That being said, I bet the 340 hp manifolds would show +- 10 hp on a mild 360 over the 360 manifolds, and both would be down 15-30hp on a good set of headers.
Click to expand...

There definitely are 360 manifolds that fit an A body, since the Dart 360 Sports had them. :) Mine did, but the previous owner put in some el cheapo headers that not only drag the ground (almost literally), the center link sometimes gets hung up on them. It's wonderful. :D

Thanks for the input on the 340 manifolds and headers, though.
 
TT5.9mag said:
Didn’t the dart sport 360s get 340 manifolds?
Click to expand...

Apparently not. As far as I can tell, they downsized them with the 360 because the 360 had a lower HP rating, since it was made during the fuel crisis years. The 360 manifolds I've seen are 2 5/8" ball connectors, which I think used 2.5 inch pipe?

The numbers on these manifolds for sale are 3418623 passenger, 3751084-1 driver. Guy is asking $100 for the pair.
 
TT5.9mag said:
In an A body? I don’t think there are any 360 manifolds (driver side) that fit an a body. That being said, I bet the 340 hp manifolds would show +- 10 hp on a mild 360 over the 360 manifolds, and both would be down 15-30hp on a good set of headers.
Click to expand...
Yeah, the 360 A bodies kept using the late (72 and 73) 340 manifolds. As far as manifolds go, I wouldn't mess with anything other than the 68-71 early 340 manifolds, as they were the best ones. The later Dakota and 1500 truck manifolds flow well and have 2 1/8 outlets. People have made them work but I don't know what all it entails.
 
Well, after more in depth searching, the passenger side is correct, the driver's side isn't. I'm going back Monday to dig through his pile of manifolds. I see a lot of listings cut off at '74 Dart Sport, but aren't the '74-76 pretty much the same?
 
273 said:
Here's a manifold/header shootout on a 300+hp 360 the difference was 1-5hp depending what rpm.

https://www.motortrend.com/how-to/mopp-0307-installing-exhaust-headers-into-300hp-crate-engine/

Horsepower​
RPM318360340SHT1 58tti1 34
2500186185187189187189187
3000223223225226228228226
3500269271272276280281279
4000299301306307314318312
4500311313315321319326321
4600311314315320317327319
5000303304308315312316311
5400281291289295282296289
Click to expand...

Wow. I thought the numbers between 360 and 340HP would be close, and really thought there would be a much greater difference between stock 360 and TTI. Thanks!
 
273 said:
Here's a manifold/header shootout on a 300+hp 360 the difference was 1-5hp depending what rpm.

https://www.motortrend.com/how-to/mopp-0307-installing-exhaust-headers-into-300hp-crate-engine/

Horsepower​
RPM318360340SHT1 58tti1 34
2500186185187189187189187
3000223223225226228228226
3500269271272276280281279
4000299301306307314318312
4500311313315321319326321
4600311314315320317327319
5000303304308315312316311
5400281291289295282296289
Click to expand...
Yeah, I remember that. Jim Laroy also did a comparison between Stock and HP manifolds and saw zero, zero, ZERO difference. So yeah.
 
Woodsman341 said:
Wow. I thought the numbers between 360 and 340HP would be close, and really thought there would be a much greater difference between stock 360 and TTI. Thanks!
Click to expand...
Guess a mild cammed 300 ish hp engine don't need much exhaust wise even the 318 manifolds do OK.
 
Woodsman341 said:
Wow. I thought the numbers between 360 and 340HP would be close, and really thought there would be a much greater difference between stock 360 and TTI. Thanks!
Click to expand...
Depends on the combination. The stock 340 and 360s were designed to incorporate manifolds. Very mild builds. "Just" bolting headers on and nothing else would garner very little, unless you also upped the ante with the carburetor.
 
RustyRatRod said:
Depends on the combination. The stock 340 and 360s were designed to incorporate manifolds. Very mild builds. "Just" bolting headers on and nothing else would garner very little, unless you also upped the ante with the carburetor.
Click to expand...

I'll probably stick with the Edelbrock 1406 that's on it now. Seems to do alright.
 
Woodsman341 said:
I'll probably stick with the Edelbrock 1406 that's on it now. Seems to do alright.
Click to expand...
Yeah, I don't know why people swallow the BS with those things. That's not even a performance carburetor. The 1405 is the performance piece and yet the 1406 out paces it in sales probably three or more to one. People latch onto to any stupid marketing. No offense.
 
273 said:
Here's a manifold/header shootout on a 300+hp 360 the difference was 1-5hp depending what rpm.

https://www.motortrend.com/how-to/mopp-0307-installing-exhaust-headers-into-300hp-crate-engine/

Horsepower​
RPM318360340SHT1 58tti1 34
2500186185187189187189187
3000223223225226228228226
3500269271272276280281279
4000299301306307314318312
4500311313315321319326321
4600311314315320317327319
5000303304308315312316311
5400281291289295282296289
Click to expand...
Wish they'd done the 64-66 273 manifolds too. Just to see if they're really that bad
 
65TerrorCuda said:
Wish they'd done the 64-66 273 manifolds too. Just to see if they're really that bad
Click to expand...
I doubt there much worse than 318 manifolds, probably 5 hp less at worse, I wouldn't over worry about on a mild early A car.

There's another shootout that I can't find anymore that included magnum manifold to and was basically same as the 340. The best was one 340 and one magnum I forget which on which side probably magnum on drivers and 340 passengers.
 
RustyRatRod said:
Yeah, I don't know people swallow the BS with those things. That's not even a performance carburetor. The 1405 is the performance piece and yet the 1406 out paces it in sales probably three or more to one. People latch onto to any stupid marketing. No offense.
Click to expand...

None taken! The previous owner put it on, I'm just getting started on this journey. I used to work on these all the time, but that was 30+ years ago. There have been a lot of new things brought out in that time...as I'm now learning. I'm always open to new ideas or suggestions, that's why I ask questions here. :)
273 said:
I doubt there much worse than 318 manifolds, probably 5 hp less at worse, I wouldn't over worry about on a mild early A car.

There's another shootout that I can't find anymore that included magnum manifold to and was basically same as the 340. The best was one 340 and one magnum I forget which on which side probably magnum on drivers and 340 passengers.
Click to expand...

Well, crap...now I have to consider Magnum manifolds, too? :)

Do they even work on an A body?
 
Woodsman341 said:
None taken! The previous owner put it on, I'm just getting started on this journey. I used to work on these all the time, but that was 30+ years ago. There have been a lot of new things brought out in that time...as I'm now learning. I'm always open to new ideas or suggestions, that's why I ask questions here. :)


Well, crap...now I have to consider Magnum manifolds, too? :)

Do they even work on an A body?
Click to expand...
Yeah there have been some folks that put them on. I think they only fit the 67 and up cars.
 
Woodsman341 said:
Well, crap...now I have to consider Magnum manifolds, too? :)

Do they even work on an A body?
Click to expand...
I think you need to do some kind of mod to them, plus there's different ones I think the earlier magnums were better, I wouldn't worry about it, your 360 ones will do.
 
Here's a good video that shows what basic mods do to a stock 2bbl 360 to a warmed over one



And mods to a mild 5.9l magnum



 
For a street car I think you are headed in the right direction - you will never feel the difference between a set of headers and 340 HP manifolds with good duals and like you say the manifolds are a lot less headaches on the street. Without a dyno or a drag strip you wouldn't even know that there was a difference.
 
Here's a brand new set of Doug's headers for a good price.

[FOR SALE] - Doug headers smallblock

I run the 71-73 340 manifolds and on the passenger side they are under 2" at their exit point. I'm going TTI longtubes over the Winter and on a stockish 340 may not see much of a gain but I do like the sound pf longtubes.
 
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