Stock 340 manifolds value

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4mulas

Fixem'up
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i have a chance to buy stock 340 manifolds, the passenger one is 68 vintage (pn 2863549)
and the drivers is 3.27.72 manufacture (pn 3614368-1)

Thanks!
 
That's sounds like the drivers side is the one with the heat stove provisions. Not a matching set.

Take price of single 68-70 passenger and take price of single 72-74 HiPo drivers. Combine price, then discount 50 or sp.
 
$400-$450 max, they can be worth more depending on condition. Someone looking for a nice '68 340 passenger will pay as much a $250-$300. The driver's 340 (72/73/74) sell for $150 -$225 in good condition. Unless you're buying it off of ebay in which case the sky's the limit.


For example...I sell the 70s 340 driver paired with the "machined" 360 magnum passenger for $325 plus shipping. They come sand blasted, and painted with high heat paint.
Treblig
 
Hey guys, what's the best combination for manifolds?
 
Hey guys, what's the best combination for manifolds?


Depends on your budget??. The 340 driver and passenger manifolds of the 60s were both 2 1/4" outlet, they were used on the 340 6 pack. The 70s 340 manifolds were a mix of the 340 driver (2 1/4" outlet) beefed up to help avoid cracks and allow for spark plug shields. While 70s 340 passenger manifolds were only 1 7/8 outlet, which made no sense because the driver's manifold was 2 1/4" outlet.

In my own opinion, the 70's 340 driver paired with the "machined" 360 magnum is the best of both worlds. You get the flow of 2 1/4" outlet for a better price. The 360 magnum also exits in a much better place than the 340 passenger. The 360 magnum doesn't crack nearly as easy as the 340 passenger (much thicker ears) and cost less to replace (more readily available) if it does crack. That's the only reason I started selling these manifolds. I prefer the 70s 340 driver because it more beefy and because the 60s driver is harder to find anyway. The only advantage to using the 60s 340 driver is that it fits the EARLY A bodies where the 70s 340 doesn't fit without major mods.

treblig
 
W have at do you mean by machined 360 manifold?


Maybe "ported" is a better word to use but it just didn't sound right to port an exhaust manifold. I grind out the outlet on the 360 magnum manifold. The 360 manifold is a very thick casting and has lots of material that can be removed to make it a 2 1/4" outlet. In fact all the manifolds I machine come out a little more than 2 1/4".

treblig

DSC03513.JPG
 
Maybe "ported" is a better word to use but it just didn't sound right to port an exhaust manifold. I grind out the outlet on the 360 magnum manifold. The 360 manifold is a very thick casting and has lots of material that can be removed to make it a 2 1/4" outlet. In fact all the manifolds I machine come out a little more than 2 1/4".

treblig

View attachment 1714952882
Is there a flow difference from the ports to the machined outlet vs the stock 1 7/8 outlet factory hipo units..?
 
$400-$450 max, they can be worth more depending on condition. Someone looking for a nice '68 340 passenger will pay as much a $250-$300. The driver's 340 (72/73/74) sell for $150 -$225 in good condition. Unless you're buying it off of ebay in which case the sky's the limit.


For example...I sell the 70s 340 driver paired with the "machined" 360 magnum passenger for $325 plus shipping. They come sand blasted, and painted with high heat paint.
Treblig

A pair of 68-70 hipo's just sold here for $450 shippedwith new bolt kit. At first advertised for $495 with no takers here: [SOLD] - 68-70 340 HP manifolds with NEW hardware kit

Another set still for sale for $400: [FOR SALE] - 340 Hi Pro manifolds

There no reason to pay the same for a set with the 72-up hi-po drivers side. Take $100+ off that actual $450 sale price if you include shipping and new hardware.
 
Question is, on a motor with 325 horsepower or less, what is the gain on the 400 dollar 340 manifolds over the log style I have on my motor? If it's only about 10 hp, then I wouldn't pay 400 bucks for 10 hp. Unless it's a resto, IS there a hp justification for the money?? My style are easy to find and sometimes can be next to free...
dscn0654-1-jpg.1714934352
 
Is there a flow difference from the ports to the machined outlet vs the stock 1 7/8 outlet factory hipo units..?


I've seen studies done on Mopar exhaust manifolds using an engine stand. There is no way a 1 7/8" outlet can flow as much as a 2 1/4" outlet...it's just physically impossible. If you "google" air flow through a pipe you'll find that if you increase the pipe diameter by 2 times your flow will increase by 4 times. So if you go from a 2" pipe to a 4" pipe your flow will increase by 4 times. There is a 21 percent increase in size if you go from 1 7/8" to 2 1/4" (actually 2.270-2.85" after machining). So if doubling the pipe size gets you 4 times the flow then increasing the size by 21 percent (roughly 1/5) you should get about a 20 percent increase in flow capacity.

If someone wants to double check me on these numbers please feel free. And yes I know that air pressure and friction play a role.

treblig
 
Great discussion guys. I was curious as to the best combination for my 70 Swinger/318. With nothing done to the engine but a 4 barrell and electronic ignition the added cost doesn't justify the gain in performance. Some pre made exhaust systems are available for 340 manifolds and I see TTI has manifold numbers listed for their systems to get the correct pipe and flange.
 
Question is, on a motor with 325 horsepower or less, what is the gain on the 400 dollar 340 manifolds over the log style I have on my motor? If it's only about 10 hp, then I wouldn't pay 400 bucks for 10 hp. Unless it's a resto, IS there a hp justification for the money?? My style are easy to find and sometimes can be next to free...
dscn0654-1-jpg.1714934352


Unless I'm mistaken it looks like to have a pair of the smaller 340 manifolds (1 7/8" outlet). Those are still bigger than the stock 318 manifolds (1 5/8" outlet). But to your point...If your have a low horsepower motor it's not worth it to buy a set of 340 manifolds or headers for that matter. Personally I think the 2 1/4" manifolds help with any engine that makes more than 290/300 horses. Everyone needs to remember that 2 1/4" outlets are of little use if you have 1 7/8" exhaust pipe!!
In my case I have 302 heads,4bbl and a mild cam, dual 2 1/8" exhaust with a 340 driver and magnum passenger manifolds. Your top RPM is also a factor, if you plan to go over 6000 RPM and you like to go to the track then headers might be a better option.
The only reason I started machining and selling the 360 magnum is that many, many FABO members don't like headers (just like I don't like headers). I wanted to give everyone an alternative to the normally expensive 340 driver/passenger manifolds. I don't need the money and it's a lot of trouble but If I can help others I'll do it.

treblig
 
If I'm going to run manifolds ( I am on Jamie's dart.) I'd go with the matched set of 68-71 style 340 manifolds. Distant second choice would be a matched set of 72-up 340 manifolds.

I personally don't like a mis matched sets or 318 ones. Performance wise I don't know what the numbers would be between them all. I know the 68-71 style are the best looking ones out of all of the small block ones
 
"REAL" 340 manifolds, are 68-70 340 HiPo manifolds. P2863549 right P2863553 left.
They are fetching from $400-$500 depending on condition. Sad, but true.

In 71 the 340 came with the same left P2863553 manifold, but went to a more restrictive P3418623 on the right. This is why people have used the HiPo left side manifold, and a magnum manifold on the right.


If you have a set of real 340 HiPo manifolds, they will wake a 318 up nicely. With a 4bbl intake, and a nice dual 2.5" exhaust, you will be pleasently surprised. Will they out flow a nice set of TTis or Dougs, no way.
But for the simplicity of bolting in, matinence, and performance, they are a great choice.
 
So let me stir this around:

Regardless of "restore correct" or "matched manifolds"

What would be the best PERFORMANCE option in an A for manifolds, IE "for each side", and must fit well?
 
Question is, on a motor with 325 horsepower or less, what is the gain on the 400 dollar 340 manifolds over the log style I have on my motor? If it's only about 10 hp, then I wouldn't pay 400 bucks for 10 hp. Unless it's a resto, IS there a hp justification for the money?? My style are easy to find and sometimes can be next to free...
dscn0654-1-jpg.1714934352
Is that your teen? Looks like a Magnum manifold on the drivers side there. It also looks like it fits well with the steering and not restrictive like the stock manifolds.
 
its so hard to take any article seriously. you have no idea what really went on behind the scene, how they manipulated things to get the numbers to show what they wanted numbers show.
 
its so hard to take any article seriously. you have no idea what really went on behind the scene, how they manipulated things to get the numbers to show what they wanted numbers show.
This is true, but until we have some trusted members come forward with valid, unbiased results from their own tests, that is about all we have.
 
"REAL" 340 manifolds, are 68-70 340 HiPo manifolds. P2863549 right P2863553 left.
They are fetching from $400-$500 depending on condition. Sad, but true.

In 71 the 340 came with the same left P2863553 manifold, but went to a more restrictive P3418623 on the right. This is why people have used the HiPo left side manifold, and a magnum manifold on the right.


If you have a set of real 340 HiPo manifolds, they will wake a 318 up nicely. With a 4bbl intake, and a nice dual 2.5" exhaust, you will be pleasently surprised. Will they out flow a nice set of TTis or Dougs, no way.
But for the simplicity of bolting in, matinence, and performance, they are a great choice.


Here they are...the 70s 340 driver and the 60s 340 driver. I (personal opinion) like/prefer the 70s manifold because of the extra ribs. It stabilizes the casting which helps prevent cracks and it gives you a place to mount a piece of sheet metal to protect the plug wires from getting burned. The 60s driver is more sleek and less bulky and much harder to find (more expensive) but they do have a cleaner look. I guess it comes down to preference???:

DSC06944.JPG
DSC06945.JPG
DSC06946.JPG


treblig
 
The 60's ones had a heat shield to protect wires. Of course those shield repros are like $200

The 70's casting has a reduced cross sectional area in the log that collects exhaust gas from the 1st, 2nd and 3nd cylinders.

It might be a very small amount, but the 72-up has to be less HP. That amount of HP difference will very per cubic inch, cam, HP, rpm, etc.

68-70 Hi-Po driver manifolds.

340%20Exhaust%20Manifold%20Pair.jpg


72-up Hi-Po driver exhaust manifold.

IMG_6641%20(Custom).JPG


72340ExManifoldComment.jpg
 
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