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

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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.
You have Super Honest Friends and I guess you are making the implication that I am not
being Honest.

Again, the National Records are Public Records that can be researched.

I seem to remember that in the Mopar Road Tests in their ads a 68/69 340 4 sp.
Cuda ran something like mid 13s (As I remember that was many years ago
since I saw it) someone on here may have the old ads. The Thermoquad Duster/Demon
are much higher real HP although rated the same and way faster. They are ever rated
15/20 HP higher than the AVS 340 cars

Where we raced at Lions Drag Strip (AKA the Beach) was arguably the FASTEST STRIP in the
country. In one weekend around 72 as I remember, over 20 National records were set at
one race as I recall (AKA The last Drag Race back then).
 
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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.
Headers, gears, and tires on an otherwise bone stock 340 Demon ran those numbers? Wow. What'd it weigh? What does that calculate to, like 400 hp? That's pretty remarkable.

What gear and tire size did it have?
 
9.00 x 30 slick were legal by then (I think ) but might have been 7 inch
slicks. I believe 4:88 rear gears and a production A833 four speed. I will
ask Rod in the morning when I see him at the track. Seems like it was somewhere
around 3100 lbs.

The records were published every week back then in National Dragster.
Perhaps someone has kept one from those days and can posted it.
Maybe, the Dragsters are stored on the internet cached somewhere (Not a computer
guy)?
 
9.00 x 30 slick were legal by then (I think ) but might have been 7 inch
slicks. I believe 4:88 rear gears and a production A833 four speed. I will
ask Rod in the morning when I see him at the track. Seems like it was somewhere
around 3100 lbs.

john, we're talking about showroom stock cars here man.
 

I'm not questioning anything anyone here is saying, but I did a quick search on Rod Green's Demon and all I could find led me back to this very site and a 14.06 time for Ron's car. Since I was like 5 or 6 years old back then, I sure as heck ain't gonna question nuthin.
 
You have Super Honest Friends and I guess you are making the implication that I am not
being Honest.
Couldn't be further from the truth. Don't assume. I said "super honest friends" because I didn't know the man with the '71 Duster, but my friends did. I'm saying it's their story but I believe them. Noth'n to do with you at all.
  • You know what? I guess I didn't pay too much attention before with your drag racing and such. But I tell you, I see a mountain of arrogance that you have a serious issue if you even "think" somebody (how dare they) call a different version from what you announce. You showed that in a post "come by and say it to my face"? For real? Because the person I know ran 14.20??? Bye
 
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Every ET and MPH and what was in the cars at the time is
exactly as I remember it. I am old enough to remember
these cars first hand and I was there. Nothing arrogant about
it = Just a statement of what I know from those days, repeated
for the information and edification for my friends on this site.

Truly, I do not really care what anyone on here thinks of me!

"Sleep well, My Friend"
Yes, at my age I do sleep well =

Just like a Baby,

I wake up screaming and with the Bed Wet every morning!


I have to go to bed now, We are going to the staging lanes
at 8:00 or a bit before.

We can continue this dialog tomorrow afternoon if you so desire.

:
 
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Every ET and MPH and what was in the cars at the time is
exactly as I remember it. I am old enough to remember
these cars first hand and I was there. Nothing arrogant about
it = Just a statement of what I know from those days, repeated
for the information and edification for my friends on this site.

Truly, I do not really care what anyone on here thinks of me!

Yes, at my age I do sleep well =

Just like a Baby,

I wake up screaming and with the Bed Wet every morning!


I have to go to bed now, We are going to the staging lanes
at 8:00 or a bit before.

We can continue this dialog tomorrow afternoon if you so desire.

:
Good luck, John! Keep us posted!
 
Vehemently Disagree!!!

Mopar ads when they were new headlined:

600 RPMs for under $3,000.

600 rpm is a good idle speed.

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

Keep in mind, the 318 NET HP was closer to 150 HP. The 318 was nowhere near the level of the 340. The 22 cubic inches were not the issue either, the differences you listed were the difference.

And probably a thousand pounds lighter than the B bodies too, great combination for a fast car :)

That is a stretch. 1000 lbs ??
 
600 rpm is a good idle speed.



Keep in mind, the 318 NET HP was closer to 150 HP. The 318 was nowhere near the level of the 340. The 22 cubic inches were not the issue either, the differences you listed were the difference.



That is a stretch. 1000 lbs ??
yes, the 340 dropped to 240 and the 318 dropped to 150. That says a lot... what was 45 hp turned into 90 hp difference lol
 
yes, the 340 dropped to 240 and the 318 dropped to 150. That says a lot... what was 45 hp turned into 90 hp difference lol
The only dyno record of a stock low cr 2bbl 318 but with headers and no accessories I know of, dyno 189 hp @ 4,000 rpm and 287 lbs-ft @ 2,500-3,000 rpm. That goes a lot better with the 150 net hp numbers then the so called 230 hp 318.

Plus When Richard dyno his low cr 2bbl 360 it made 231 hp with manifolds and 264 hp with stock 4bbl intake and Qjet and manifolds and 277 hp with headers, plus at this point still had the water pump and alternator on it too.

I can't see a 340 with cam cr and more head flow being this low (360 #), even the weaker low cr 340 would probably have gross hp dyno numbers close to 275 hp.
 
Here's a dyno of a stock 273 Commando with manifolds and headers.
It basically hit it's stock hp number 233.4 hp.

A 340 only makes 40 hp more ?

https://www.hotrod.com/articles/testing-mopar-273-power-pak-dyno/

1744350726928.png


"TTi headers are about the best on the market for our unconventional Mopars, but we were warned to make sure our small 273 exhaust port windows fit properly. Sure enough, the generous TTi flanges (which are sized for 340/360 heads) left large leak paths. We remedied them by welding up the bottoms (pen shows them in photo) to match the 273 port windows. The extra exhaust flow delivered 244.2 hp at 5,100 rpm and 283.4 lb-ft at 4,000 rpm, gains of 10.8 hp and 6.6 lb-ft."
 
320 hp seems hard to believe....
The test below was done back in the day, with engines removed from the car & dyno tested

img161.jpg
 
273,
Yes 295 hp for the 340, as it comes in the car.
So in dyno trim (gross hp) it would be more than 295 hp, maybe not all the way to 320 hp but a lot closer.

To me I don't overly care what a stock 340 makes, but every sense I have says it's a least 300 hp gross and a 230 hp 318 doesn't make over 200 hp.
 
273,
The purpose of the test was to see if the engines produced the advertised hp. The 340, as you can see, was the only one that did...& exceeded it.
 
Remember those guys that bought into the old rumor of a Wednesday car?
The theory that a car built on a Wednesday was somehow a better built car because on Mondays, they were hung over from the weekend and on Friday, they were looking forward to quitting time and the weekend. Somehow, cars built mid-week supposedly had more attention to detail?

01 A1.jpg


Sometimes though, an engine runs much better than the rest. Maybe a positive tolerance stack up?
I've driven numerous Chevy 350s. Some were gutless, some hauled ***. One was in a 75 Camaro owned by my Brother's friend. It idled smooth but flat out scrammed. I once had a 318 that wouldn't even peel out in gravel. That one had a timing chain replaced and somehow, it was THREE teeth retarded on the timing sprocket! Once I found that and replaced the chain and sprockets, the dude hauled ***!
 
273,
The purpose of the test was to see if the engines produced the advertised hp. The 340, as you can see, was the only one that did...& exceeded it.
Why the line through the text ?

Fair enough, pretty much the point of this thread if the 340 exceeded it's rating and bet most agree it did, then question is by how much, where generally the arguments start.

You said you couldn't see 320 hp but you own proof shows 295 hp with a basically net rated, so the engine measure in gross probably be pretty close to 320 hp.

What would be gross nowdays generally be

best tune

no accessories

electric water pump

headers but to find stock gross #'s running manifolds would be better

I don't see it being hard to pick up the extra 25 hp with those conditions but even if not it's still seems to be at least a 300 hp engine.
 
Why the line through the text ?

Fair enough, pretty much the point of this thread if the 340 exceeded it's rating and bet most agree it did, then question is by how much, where generally the arguments start.

You said you couldn't see 320 hp but you own proof shows 295 hp with a basically net rated, so the engine measure in gross probably be pretty close to 320 hp.

What would be gross nowdays generally be

best tune

no accessories

electric water pump

headers but to find stock gross #'s running manifolds would be better

I don't see it being hard to pick up the extra 25 hp with those conditions but even if not it's still seems to be at least a 300 hp engine.

It’s very easy to make over 400 hp with a 340.

It takes ZERO port work, a Strip Dominator, good headers and a cam with 280 degrees of advertised duration.

And you can shift it at 6k.
 
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