Stock 340 redline

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Hadahemi

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Just a passing thought, I was wondering what kind of RPM limits are considered reasonable for a stock 340. If some of you run higher than stock redline, what modifications have you done to the engine?
 
ported heads and a big solid cam, Mine went to 7200rpms. Srock crank and rods, Lightened Ross pistons.
 
Mine is build for 8000-rpm. roller drive train/solid roller cam, everything is balanced, lightened ported and/or polished. Victor 340 with an 800 double pumper on top.

Cut my headers and 3" exhaust off... Went with manifolds and 2.5" exhaust.... No point in turning it to 8,000 anymore but it is built for that.
 
You'll probably start seeing valve float above 6000/6200 rpm in stock setup.Would want to shift around 5200/5400 max. I have a .030 over 340 with stock bottom end except for TRW pistons. lift is about 513 on my cam with rhoads lifters & heads are ported x units with port matched rpm air gap intake and I still get best times shifting at only 5600/5800rpm.

Oldschoolcuda
 
Yeah, Mine isnt really a stock 340 is it ?

Bone stock I would think 6000rpms isnt out of the question.
 
What about bearing oil clearances on the rods and mains for higher RPMs, still use stock clearances?
 
I would think if you blue printed the motor paying attention to machining, balancing, Bob weight, correcting valve train and lightning the rotating assembly you could probably spin it to 6500rpms. Im, not sure the heads will flow enough to really use that RPM though.
 
mine is balenced trw 10.5s port matched iron manifolds tti2.5 purple .455 268 272 273 rockers holly 670 .it likes 6000. axidentaly went to 6500 once. cam is rated to 5800.
 
Most stock 340`s seem to spin good to about 6000 rpm. After 6K they`re just not making much power without mods. I think the `69 dealer advertisement read "6000 rpm for less than $3000.00".
 
Mine was a 340 4spd all stock with x heads new springs Eddy RPM performer Demon 650 484 purple cam and Dons complete ignition system from www.4secondsflat.com...... stock rods, pistons, heads....

It would pull all the way up to 7200 RPM all day long no problem and I think there was more left in it......
 
Stock 68-71 340 will spin to 6000, but why?

It's not making any headway up there. I shift mine which is slightly better than stock at 5500. A stocker, might be good for about 5200-5300 still making power.

Modified they'll spin a bunch as noted by some of the responses here.
 
AdamR said:
I believe that is correct, But max power was advertised at 5000rpms.


http://www.340swinger.org/tech/69options3.html
Click to expand...

It would be interesting to see a stock `68 340 on the dyno to see what kind of power it made and where the power curve rises and falls. There was a lot of manipulation with hp numbers in the late 60`s in an effort to make a powerful engine yet rate it in such a way that car owners could afford insurance.
 
stock 340s came with hydraulic cam and single wire valve spring...probably not going to get much over 6000 rpm...and as said wont run any faster at that rpm
 
Here are the HP numbers on a stock 68 from old info. i've accumulated. Test performed on Edelbrock's dyno with aircleaner installed & total advance set at 39 degrees.

Oldschoolcuda
rpm hp
2100 111
2500 138
3000 181
3500 218
4000 247
4500 264
5000 278
5500 280
6000 272
 
That is a good article. I`m running a big block carb on my stock 340 and I knew it helped some but never knew it could be worth 35 hp. Wow! As most guys have said, it doesn`t look like a lot is gained by turning the engine much over 5500 rpm.
 
I know it isn't a stock 340 but...did you catch the article in one of the Mopar mags last month, that ran a 6-pack setup on a Mopar Performance 340 crate motor? With the MP 284*/.484 cam, it pulled to high rpm...6800 rpm? 7200? I forget...it was up there. 390 HP they got with some tuning.

I'll look it up and see what mag that dyno test was in...

Edit: It was in the Mopar Muscle August issue; and it was the .508 cam. Made 388 HP at 6800 rpm, was still climbing.
 
Stock redline was 6,000. I ran 14.28 with my pure stock 340 Swinger back in early 1970 with 727, 3.23 non-SureGrip on Goodyear Polyglas tires at OCIR shifting at 6,000.
 
Hadahemi said:
AdamR, that Comp cam read was great, thanks for the input everybody
Click to expand...

Your welcome, That,s probably pretty real world too. No fancy machine work. Close to the standards that you would see from the factory.
 
ocdart said:
Stock redline was 6,000. I ran 14.28 with my pure stock 340 Swinger back in early 1970 with 727, 3.23 non-SureGrip on Goodyear Polyglas tires at OCIR shifting at 6,000.
Click to expand...


I wonder what the record is for a pure stock drag 340 is now. I wouldnt be surprised if theres a few 340 A's in the very low 13s or high 12s.
 
AdamR said:
I wonder what the record is for a pure stock drag 340 is now. I wouldnt be surprised if theres a few 340 A's in the very low 13s or high 12s.
Click to expand...

Back in 1970 Chrysler created and promoted Plymouth's Rapid Transit System for new high performance Plymouths. The RTS was the source for many magazine advertisements and I still have a few Hot Rod mags in pristine condition which feature the multi-page spread for this campaign. Part of the criteria used to become a member of the RTS was that the car had to finish the 1/4 mile in under 14 seconds flat, and hit 100 MPH.

The 1970 Duster 340 was part of the RTS, and was tested by none other than Mopar legend Ronnie Sox. Sox drove a factory showroom 1970 Duster 340 with factory 4 speed and a 3.91 Sure Grip to a 13.9X ET on stock E70-14 GoodYear raised white letter PolyGlas rubber.

Many articles from back in those days listed Chrysler engineers as saying that pushing a stock 340 beyond 5500 RPM was not productive as the stock 340 was maxxed out in the torque and horsepower curves at that point.

Of course, with a few mods, 6,000 RPM or a little more is quite achieveable.

The point of all this--- shifting a stock 340 beyond 5500 / 5600 RPMs does not produce any better results --- but then again --- who stays Stock?!!!
 
hi, on our NHRA stocker 340's, shifted at 6300-6500 max, geared for 7200 at the stripe. we found , they don't like to be shifed at any thing over 6500, they lay down badly!!
 
Here`s a neat article I found some time ago that gives the real #`s on the 340 and Ronnie Sox`s driving skills.

Plymouth tells it like it is.jpg
 
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