Its already been doneWe need a dyno shootout.
compared 340 manifolds shorty and long tubes
as recall they were about the same as the stock 340s maybe 5hp up top down low the same
think 273 posted the vid
68 340 Exhaust Manifolds vs TTi Shorty headers
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compared 340 manifolds shorty and long tubes
as recall they were about the same as the stock 340s maybe 5hp up top down low the same
think 273 posted the vid
Installing Exhaust Headers Into 300hp Crate Engine - Exhaust Blowout
Read on as we dyno test our installed exhaust headers and exhaust manifolds into our Mopar Performance 300hp crate engine. Read on for more details along with photos only in Mopar Muscle Magazine
Nick did one with a 72 (I believe) 340. Headers were 357.7 @ 5800 rpm and 72074 manifolds were 341.3 @ 5700 rpm.
For 16 horsepower, I don't think a $800 set of headers is worth it on a mild built 340. They bumped the compression a bit, 2,02 intakes, a little bowl blending and a little bigger cam.
For 16 horsepower, I don't think a $800 set of headers is worth it on a mild built 340. They bumped the compression a bit, 2,02 intakes, a little bowl blending and a little bigger cam.
A56
Street Survivor
I know but it was the first small block dyno video I saw.Oh boy, you may have opened a can of worms with this guy.
DionR
Well-Known Member
6hp 5lb ft of torqueInstalling Exhaust Headers Into 300hp Crate Engine - Exhaust Blowout
Read on as we dyno test our installed exhaust headers and exhaust manifolds into our Mopar Performance 300hp crate engine. Read on for more details along with photos only in Mopar Muscle Magazinewww.hotrod.com
And as I argued here, that is a completely pointless test for anyone that has a cam in their motor bigger than a 2BBL cam. And I'm not so sure a late 60's 2BBL isn't actually bigger than the stock 5.9 Magnum cam.
You can't use that test to validate anything unless you are running the same motor. Even the best headers only made 16hp more than the 318 manifolds. For that, why spend $1K for TTI's when cast off 318 manifolds are almost as good?
The way this test is references, seems like people are wasting their money putting headers on their 408's.
That test is worthless to anyone not running a stock 5.9 Magnum or maybe a stock 2BBL 360 out of a van. People need to stop pointing to it as the Holy Grail of exhaust tests.
Super-Cuda
MOPAR .. Move Over, Plymouth Approaching Rapidly!
Guys, just to add my 2 cents to this conversation, there's more to consider here than just hp. loss when choosing shortie headers.
For me , it was the extra clearance and serviceability of the complete TTi system as I was fed up with burned hands, scraped knuckles, bending and denting tubes on brand new and expensive but poor fitting other long tube makes and I had 3 different sets on the car.
Now, I get in and drive.
If I want to pull a plug or drop the complete system, its way easier, especially now that I'm older.
For me , it was the extra clearance and serviceability of the complete TTi system as I was fed up with burned hands, scraped knuckles, bending and denting tubes on brand new and expensive but poor fitting other long tube makes and I had 3 different sets on the car.
Now, I get in and drive.
If I want to pull a plug or drop the complete system, its way easier, especially now that I'm older.
DionR
Well-Known Member
I wonder what the '68-71 PS manifold would have done for it. The DS manifold still has the big outlet so even though it has wings for the heat stove, it shouldn't give up anything compare to the earlier one.
This test would have been interesting if he had put some 318 manifolds on it at the end. That would have been a test I could get behind using for the average enthusiast without a stroker motor.
For comparison sake, the Hot Rod exhaust test has the 340 manifolds down 4hp to the Hedman headers at the peak and the biggest difference was 8hp. But that was with the real 340 Freeflows, not the half assed '72+ setup. And I looked at the Hedman results rather than the TTI's because it looks like Nick's test used something other than TTI's as well.
A56
Street Survivor
I wouldn't miss 8 hp on a street car regardless.
Exactly, and like they said, unless you are a serious racer, are the headers worth the extra money for a handfull of horsepower? Header power would improve with a little carb tuning but the A/F ratio stayed the same in the tests. I bet the HP manifolds would be closer to the Hot Rod test. They are a pretty well designed manifold. They do have their limits though.
Installing Exhaust Headers Into 300hp Crate Engine - Exhaust BlowoutWe need a dyno shootout.
Legend318:Stock '69 A-Body exhaust manifolds with 24-inch extensions360:Stock '77 360 iron log-style exhaust manifolds with 24-inch extensions340:Stock '70 340hp exhaust manifolds with 24-inch extensionsSHT:Hedman 151/48-inch-tube shorty headers with 24-inch extensions 1 58: Hooker Competition 1 58-inch ceramic-coated header tti: Tube Technologies Inc. 1 58x1 34-inch chrome step header 1 34: Hooker Super
Competition 1 34-inch header; bare, uncoated
| Dyno Results | |||||||
| Westech Engine Dyno Superflow 901 | |||||||
| Torque | |||||||
| RPM | 318 | 360 | 340 | SHT | 1 58 | tti | 1 34 |
| 2500 | 391.3 | 389.5 | 392.0 | 396.1 | 392.9 | 397.4 | 392.3 |
| 3000 | 389.0 | 390.1 | 394.3 | 396.5 | 398.4 | 399.5 | 395.8 |
| 3500 | 403.0 | 407.1 | 408.3 | 414.5 | 420.5 | 421.1 | 418.3 |
| 3700 | 400.2 | 404.7 | 409.1 | 413.7 | 423.9 | 425.5 | 420.7 |
| 4000 | 392.7 | 395.5 | 401.2 | 403.4 | 411.9 | 417.4 | 409.9 |
| 4500 | 362.6 | 365.8 | 367.1 | 374.1 | 372.7 | 380.9 | 374.3 |
| 5000 | 318.4 | 319.5 | 323.7 | 330.7 | 328.1 | 331.6 | 326.3 |
| 5400 | 273.2 | 283.5 | 281.4 | 286.6 | 273 | 287.6 | 281.3 |
| Horsepower | |||||||
| RPM | 318 | 360 | 340 | SHT | 1 58 | tti | 1 34 |
| 2500 | 186 | 185 | 187 | 189 | 187 | 189 | 187 |
| 3000 | 223 | 223 | 225 | 226 | 228 | 228 | 226 |
| 3500 | 269 | 271 | 272 | 276 | 280 | 281 | 279 |
| 4000 | 299 | 301 | 306 | 307 | 314 | 318 | 312 |
| 4500 | 311 | 313 | 315 | 321 | 319 | 326 | 321 |
| 4600 | 211 | 314 | 315 | 320 | 317 | 327 | 319 |
| 5000 | 303 | 304 | 308 | 315 | 312 | 316 | 311 |
| 5400 | 281 | 291 | 289 | 295 | 282 | 296 | 289 |
A56
Street Survivor
I believe even on the better early 340 exhaust manifolds there is some room to "clean" them up for a little more efficiency.
DionR
Well-Known Member
Pointless. See my response in #31.
I somewhat agree with ya obviously results can very.
Who's gonna use this test to decide on a built engine, most deciding manifolds vs headers are on mild engines.
Yes would of been better with an engine that had some cam, it's not the holy grail but is best we got, you say it ain't anywhere near accurate but got any conflicting dyno results ? On mild applications.
Most of us can't afford to R&D the best possible combo so it takes the best guesstimation with the info available to us, should people take the above results with a huge grain of salt, yes.
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Inertia
Well-Known Member
Do you think that the tests shown above indicate exactly what the question asks.
Do headers increase power by improving exhaust flow.
Folks used to scoff, say headers only work over xxxxx rpm.
In fact, the test show better results at near idle.
I suggested years ago that headers would even improve town driving fuel mileage, and test results indicate you'd use less gas pedal going shopping.
The 1 st test is fine as shown
But, again going to the air pump logic. . .
If you keep the restrictive puny exhaust system, designed for a specific exhaust flow, even making cast-iron manifolds with runners for direction, bigger passages etc, all to easy exhaust flow, . . . Why ?
Keep the 2 1/2" exhaust system, - (pump outlet), - - - then add a 4 barrel, a high-rise manifold, bigger camshaft, bigger heads/valves, bore, pistons.
Essentially open up the "air-pump" opening to 6 inches . . . AND ignore the puny, untuned, unscavenged exhaust, that every race engine in the world designs with great attention to the "few" horsepower improvement goes against all logic.
Ever looked at/studied F-1/Indy car exhaust systems .
I look for performance by the ounce, - everywhere.
Good luck
Do headers increase power by improving exhaust flow.
Folks used to scoff, say headers only work over xxxxx rpm.
In fact, the test show better results at near idle.
I suggested years ago that headers would even improve town driving fuel mileage, and test results indicate you'd use less gas pedal going shopping.
The 1 st test is fine as shown
But, again going to the air pump logic. . .
If you keep the restrictive puny exhaust system, designed for a specific exhaust flow, even making cast-iron manifolds with runners for direction, bigger passages etc, all to easy exhaust flow, . . . Why ?
Keep the 2 1/2" exhaust system, - (pump outlet), - - - then add a 4 barrel, a high-rise manifold, bigger camshaft, bigger heads/valves, bore, pistons.
Essentially open up the "air-pump" opening to 6 inches . . . AND ignore the puny, untuned, unscavenged exhaust, that every race engine in the world designs with great attention to the "few" horsepower improvement goes against all logic.
Ever looked at/studied F-1/Indy car exhaust systems .
I look for performance by the ounce, - everywhere.
Good luck
DionR
Well-Known Member
But this same motor made like 50hp more with a mild 262ish cam. This isn't a mild engine, it's what an enthusiast would start with before they toss the cam in the recycling bin. Even if they are down on cash and run it like this, I expect they would put a cam in it at some point down the road.
And frankly, seems like I see this test come up on all kinds of builds, and most of the time nobody even asks what the motor is before they start trumpeting how worthless this or that is using this test. Look at the reference I linked in my first response, the question was if the 340 manifolds would fit in a chassis and no one asked what motor he was building before bringing up this test and telling the OP they weren't worth trying to fit.
I'm not the one that has to validate anything. If you want to apply it to a broad range of motors, you are the one that needs to show that it can be applicable. I'm saying is too narrow focused to be useful for anything beyond a stock 5.9.
I will say that the video from Nick's Garage seems more useful to me than the HR magazine test, but I haven't watched it all and I get the impression some don't trust Nick or something. But from what I've seen so far, it must have a bigger cam than the broomstick the stock 5.9 has since it appears to peak 1400 or so RPM higher.
No argument beyond my opinion that most times that I see the manifold test put up, it is taken with a huge grain of sugar instead of salt.
ive seen other test with a stroker motor with manifolds much larger cam still was not a big difference
ive seen 5 or 6 other test where they add 15 to 20hp long tubes with a 220@50 cam or better
guys run 10s with the early 340 manifolds enough said
800 for tti no farking way for 20 hp
put a 150 shot on it with cut outs on demand doesnt beat the engine all the time stall friendly gear friendly mpg friendly
shorty headers at zilch would be worse on a bigger cam comp setup thats been done as well
That's Still mild.
The OP is only asking about fitment far as I know, the one thing the test does show and what is my main take away from it there ain't much difference between manifolds, manifold aren't tuned, don't aid scavenging just a restriction and it shows ain't much difference between 318/360/340 and in another test magnum (and probably 273's), if OP was ok with going 340 manifolds then 360 or magnums will do too. Plus shorties in every test I see are basically slightly better than manifolds there not tuned for any rpm most of us turn.
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DionR
Well-Known Member
I agree. And it makes the motor in the manifold test absolutely meek.
Who's debating manifolds vs headers on 400 - 500+ hp engines very few, more than likely under 400 hp, 250-350 hp is where most probably would be wondering is it worth it.
DionR
Well-Known Member
I would agree with using that test for validating that each made a difference.
My issue is that it doesn't stop there and it becomes an "X is worth Y" argument and people want to use it to say 340 manifolds aren't worth anything.
I'm not arguing that 340 manifolds aren't as good as headers. I'm just saying we don't really know how much they would lose if the cam wasn't so small.
Maybe the cam isn't the bottleneck, maybe the 340 manifolds are worthless over 318 manifolds if the cam were bigger, lots of maybes. But all we have are maybes in regards to those questions. The only data is that each is better than the last (for the most part) and we need to stop suggesting that based on this test that 340 manifolds are worthless.
Yep, if you are deciding, use a little common sense and look at your checkbook balance. If it's a small cam Teen with a 4 barrel, headers really aren't needed. A basically stock 340, I wouldn't. I would just use the HP manifolds and rock on. You could still run it down the drag strip for fun. Of course, if it turns out to be a dedicated drag car, then it get's headers. Just a little common sense. I'm more conservative, I have no need to burn the tires off for a city block and 6 horsepower won't make much difference.
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