Stock 340 dyno tests?

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IQ52

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I haven't driven a stock 340 since 1969 so it's difficult for me to remember just how fast the '69 Dart really was. Today I began some searches for some stock 340 dyno tests. Here are two I hope that may shed some light on the 340 output.

#1stock to modified

Note how #2 was built to stock specs before the dyno test.

#2stock? 340 build

Any other stock 340 dyno tests out there we can look at?
 
IQ52 said:
I haven't driven a stock 340 since 1969 so it's difficult for me to remember just how fast the '69 Dart really was. Today I began some searches for some stock 340 dyno tests. Here are two I hope that may shed some light on the 340 output.

#1stock to modified

Note how #2 was built to stock specs before the dyno test.

#2stock? 340 build

Any other stock 340 dyno tests out there we can look at?
Click to expand...


That last article could have made another 20-35 HP if they took off the big headers and put some 1 5/8 headers on it.
 
First article, Dyno Derby, is garbage. Stock headed/rocker armed XE268H making almost 400hp, yeah sure it is.
 
Seems like there are a lot of opinions and very few facts on stock 340 horse power.
 
I thought the 340's 275 hp rating was realistic and not conservative as with some other engines? The 316 hp in the above mention build was somewhat believable with an optimistic dyno but getting to 400 hp with a mild cam, intake and headers is a stretch.
 
i think 275 was conservative. I think the 340 had more than 45 more hp than a 318 2bbl. Consider X-heads, 4bbl, hotter cam, and 22 more cubes ... Seems most believe 310 hp was more realistic. But maybe the 318 2bbl only had 200 hp instead of the 230 hp advertised.
 
Most 340 cars were FUN to drive even bone stock. Ain't that all that counts?
 
96 to 98 mph in the 1/4 is 250ish rwhp at 3500 to 3600 lbs sitting on the line thats 300 plus crank hp thats high 13s 14.0 stock with a tune and traction
the carb was 20 hp restriction fix that you got mid 13s@100 -101 low 13s in the cards for the light weight notch cuda
thats what they turned if you had a clue
 
Too much is made of hp.
The 340 a body was just well balanced and quick.Pulled hard from the lights to well past highway speeds with decent mileage!
 
Consider an D, E or F/ Stock 340 car per NHRAs parameters. F cars at around 3300 pounds run in the 10s. Stock cast iron intake and heads, 3 angle valve job only, stock valve size. Cam is limited to STOCK lift .467 any duration. Max .70 overbore with stock compression, stock stroke. STOCK AVS 68-70 TQ in 71. The good engines average 126 mph at 7600 rpm in the traps. SO how much HP does a STOCK 340 pull? I know some will say they’re built like a Swiss watch but with STOCK parts?
 
ir3333 said:
Your post is gonna' be hard on Airgap sales.
Click to expand...
A friend who had a 73 H stocker, and he put an air gap and an AED 850 on it and ran the same number. This is the TQ, low compression small intake valve, still ran 11.0s
 
ir3333 said:
Just too much product advertising to be believable.
Click to expand...
I don’t see it that way but I do understand your point of view.
When you say product advertising, I see them saying what they used. There not paid by any company’s part they use.
 
318willrun said:
i think 275 was conservative. I think the 340 had more than 45 more hp than a 318 2bbl. Consider X-heads, 4bbl, hotter cam, and 22 more cubes ... Seems most believe 310 hp was more realistic. But maybe the 318 2bbl only had 200 hp instead of the 230 hp advertised.
Click to expand...
Here's a stock 318 2 bbl with headers made 189 hp, even with a bump in cr and ran with exhaust manifolds doubt it would do better.

318 Long Block Bolt Ons - Tech Articles - Mopar Muscle Magazine
 
The 340 did come with a pretty mild cam I wouldn't be shocked if it was 275 hp especially with stock tune, but I think it was slightly underrated, probably more like 300 hp. The 245 hp was net add a bit more for cr and better head flow so say more like 265 hp net for the 275 hp doudt only loss 10 ish hp gross to net. Really don't matter was a great package that responds well to mods.
 
Build #1 from Post #1 is exactly my 340 except for the carb. I have a 750 instead of an 800. So I figure I am probably about 15 or 20 HP under the 392 number. That is why I say my 340 is about 375 HP.
 
No way did you loose that much HP from the carb difference.
No way, no how, fageddaboutit!
 
340 was rated at 5000 rpm. It might have made 285-290 at 5300-5400. Every one I've ever seen in stock form didn't do squat for power increase over that 5300 number.

Hate to say it but an XE268H with stock heads/rockers with an RPM intake/carb is a 1.0ish hp/ci formula.

Putting a good valve job on these things makes a big difference. The factory stuff... MEH. Might be why these "stock" rebuilt engines tend to run better with machining tolerances and better products going into the build. The days of drive it 500 miles to knock all the crappy machine work into shape... gone.
 
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