340 4 barrel and 340 6 barrel: were they really UNDERrated?

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No Big Secret that a 71 340 Stock Eliminator engine
makes upwards of 500HP. Our engines are currently
rated at 314 and 311 depending on heads.

If you cannot make 1 1/2 your NHRA rated HP you are
not even in the Ball Park! Try 2 times the rate HP for SS.

Still waiting to get into the pits at 4 Wide.
 
I believe this to be true and believable as the 4 speed cam was discontinued as of January 1968 I believe. The b body cars were the bread and butter of Chrysler Corp in 1968. How would you feel after buying a 68 road runner or charger only to get spanked by a 340 dart or Barracuda stop light to stop light or worse at the dragstrp?
So with the smaller cam and the puny little avs carb, the 340 in the lighter a body came seriously close to big block b bodies performance while the b body cars had a higher price tag.
 
rklein383 said:
Don't know about being underrated. My 340 Cuda with cam and bolt ons would lose by a car length to my best friend's 383 Super Bee with headers every time. Both had 323 gears. Looking back, I think the Torker 340 manifold was a mismatch to the cam.

View attachment 1716390901
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Your Cuda motor in an A body would have beat that Superbee every time. (weight)
 
I've always wanted to blueprint a 68 4 speed 340 with the 71 induction system on top. "Maybe" hang some BIG tube headers off the side and let that be it.
 
I remember reading an interview with a retired Chrysler dyno operator who stated that he had never seen a 340 that made less than 320 horses.
Here's my reasoning for why Chrysler rated them at 275 hp.
First off, insurance companies were charging much higher rates for any cars that were rated over 300 hp, which discouraged sales. Secondly, when the 383 was rated at 335 hp in a b body, how much would the a body sales have cut into the b body market if they were advertised as 320 hp in a Dart? Smaller, lighter, and less expensive than a b body?
They weren't going to cut their own throats and kill sales of Chargers and Super Bees by doing that, so the 340 got rated as 275 hp @ 5000 rpm, which was probably fairly close, but push it to 6000 rpm and hold on!
 
GTX JOHN said:
No Big Secret that a 71 340 Stock Eliminator engine
makes upwards of 500HP. Our engines are currently
rated at 314 and 311 depending on heads.

If you cannot make 1 1/2 your NHRA rated HP you are
not even in the Ball Park! Try 2 times the rate HP for SS.

Still waiting to get into the pits at 4 Wide.
Click to expand...
I'd just love to have an inside look and explanation on how that is done.
 
crackedback said:
How come none of these 340 cars were ripping off 105+mph 1/4's in stock form when new? Goes for the 330-370hp chevies too.

340's are kind of dead at 5200-5400 in stock form

If you got one that ran even 100mph, you got a good one.

Don't miss out on the "minor bowl work, roller rockers and lighter rods" part of that 320hp mill....
stock rockers are lucky to be 1.42-1.43 and replace them with a true 1.5-1.55 rocker
Minor bowl work, add 15 cfm to the flow rate and filling under the curve...
More flow, more lift... Nope, none of that will matter
Click to expand...
 
Vehemently Disagree!!!

Mopar ads when they were new headlined:

600 RPMs for under $3,000.

My Friend Rod Green's 340 Demon right of the showroom
ran 13.05 @ 105 with the stock Tires an zero modifications.

A few years later with Header/Gears/Tires he set the NHRA National
Record in Fremont = 11.88 @ 113.20 with the engine never out of the car.
I was there helping him!

With the engine gone thru Stock Eliminator style many years later and a set of heads and intake of
my car in Vegas it set the H/S National record 10.82 @ 120.02 in the same Demon.

Even with the weak about 100 on the seat and about 250 open they would turn 6500 RPM
regularly. The only problem was even with the stronger 340 stamped stock rocker and pushrod
they would ran a pushrod through a rocker back then every now and then.

We have been friends all this time and Rod is right here helping me this week at Nationals and
next week at the double divisional and we both still race our 340 cars fifty plus years later.
Of Course, they are faster these days. Another gentleman Tom set the D/SA National Record
in Eagle Idaho in his 71 Duster 340 a few years back in the NINES!

The National Records are public information and can be researched with a just a little effort
for those who are curious.
 
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Underrated? I'd guess so....
1971 340 = 275 HP
1971 318 = 230 HP

So the bigger bore, bigger cam, bigger heads, bigger intake, bigger exhaust, better compression, 4bbl vs 2bbl .... all that is only 45 HP... Hmmm
 

GTX JOHN said:
My Friend Rod Green's 340 Demon right of the showroom
ran 13.05 @ 105 with the stock Tires an zero modifications.
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Interesting. I knew somebody that bought a new 340 Demon, automatic with 3.91's and with 300 miles on it they ran it with slicks (slicks the only addition) and it went 14.20
 
Rods car was a factory 4 Speed 3.91 gears Demon with original 14 inch tires.

My elderly father's 70 340 Duster with 3.23 open rear, back when new ran well into the 13's
when it was new.
 
273 said:
Wouldn't track, elevation, temp, Driver, tuning etc.. play a role in some of these disparities
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If Driver Skill/Tuning/Mechanical Aptitude did NOT play a role in the disparities:

Theye would not be 50+ NHRA National Event Class Win "Wallys" on the shelves
and a wall with NHRA National Records and AllStars Certificates in our shop.
Hopefully a couple more when we run Class next week in Las Vegas as we are
not quite done yet.

As I said above, the records are public information and can be researched and
documented if you want to spend the time!

I only come on this site to help you guys and buy and sell some stuff.

If I want to get in a fight, there are several Bars in our little town that I
can do that without as much work!
 
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crackedback said:
Not a single 71 Demon 340 tested back in the day ran better than 14.20 IIRC.

14.00 at best and high 90's were the norm for 340's.
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I had some really good Mopar friends that were super honest and had high end cars. They had a friend (they told me) that had bought a new '71 Duster, 340 4 speed, and tried for a year to get a 13 second pass. They tried different RPM launch's and shift points, they tried adjusting the metering rods and timing (only turning the factory adjustments, no altering), but never got their 13 second pass. They would go 14.0X's to 14-teens. But never got a 13.99.
 
If you esteemed Gentleman are calling me a LIAR and DISHONEST....
I am at most Western races = Come on by and tell me I am a LIAR to
my Damn Face if you have a pair!!!

Those that Can = DO!
Those that Can't= Sit on the Sidelines and Hoot and Throw Mud!

Arguing with you Gentleman is Like Playing Chess with a Pidgeon:

He knocks down all the Pieces.

***** on the Playing Board.

And Struts around telling everyone he won the Game!!!
 
GTX JOHN said:
If you esteemed Gentleman are calling me a LIAR and DISHONEST....
I am at most Western races = Come on by and tell me I am a LIAR to
my Damn Face if you have a pair!!!

Those that Can = DO!
Those that Can't= Sit on the Sidelines and Hoot and Throw Mud!

Arguing with you Gentleman is Like Playing Chess with a Pidgeon:

He knocks down all the Pieces.

***** on the Playing Board.

And Struts around telling everyone he won the Game!!!
Click to expand...
woah, sleep easy my friend. I said "interesting". that's not "liar". I can report results just like you. And I did. Get used to it, and good night :)
 
GTX JOHN said:
If Driver Skill/Tuning/Mechanical Aptitude did NOT play a role in the disparities:

Theye would not be 50+ NHRA National Event Class Win "Wallys" on the shelves
and a wall with NHRA National Records and AllStars Certificates in our shop.
Hopefully a couple more when we run Class next week in Las Vegas as we are
not quite done yet.

As I said above, the records are public information and can be researched and
documented if you want to spend the time!

I only come on this site to help you guys and buy and sell some stuff.

If I want to get in a fight, there are several Bars in our little town that I
can do that without as much work!
Click to expand...
I'm not questioning ya, far as I've been told your our resident expert on such things, but I also respect 318willrun's insights why I tried to solve maybe why there's some disparities.
 
Well, I am pushing 80 years old as most folks know on this
site. Many of whom I have try to Help at least a few times on this site.

NO magic beans... Just facts as a lot of folks on here who have followed us
are aware of.
crackedback said:
Get over it... Remember how you answered MY post. Be Vehement! How old are you wanting fight people? Good job.

Show one tested car, in a magazine, that ran those numbers in FACTORY form. Not some friend of yours.
Even Ronnie Sox didn't do those numbers in a stock equipped OEM 340 car from the factory.

Whatever. You guys had a magic bean, great. Now I'm out...
Click to expand...
 
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