340 valve springs

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69swinger340391

69swinger340391

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I am looking to replace the original valve springs on my '69 340. What is a good replacement spring, with maybe a little more spring tension, as the car revs to about 5000 rpm where it then feels like the valves are floating.

What about a tool to do this with the heads installed in the car. I see them for the stud type rockers but not the Mopar shaft type.

Thanks
 
On a stk can new stk springs are enough buddy. You need to put air in the cyl is the best way, and there are a few tools that work on mopar, can not find a number, mine is worn off. look on snap on site...
 
Take a spark plug to the hardware store with you.

Find an air fitting or adapter with the same thread.

Clamp a hose on it with the fitting to hook up to your air compressor on the other end.

Do one cylinder at a time, making sure to turn the engine until the exhaust just closes (you are then on the base circle for that cylinder) and then pressurize the cylinder.

Use a typical inexpensive spring compressor (screw and hooks type, should be available at local auto parts store).

Keep a few magnets around the valve area and put clean rags in the cylinder head openings to avoid any keeprs or retainers getting dropped in.
 
I have this cam in there now:

Mopar Performance P/N P4452761

0.450 int./0.455 exh. lift
Duration: 268 int./272 exh.

It is slightly bigger than the stock cam

I have heard good things about the Comp Cams 268, would a stock replacement spring work well with that as well?

Thanks
 
http://cgi.ebay.com/ebaymotors/NEW-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Check these out while I look at some others.
They are Elgins and the price is right.
16 NEW ELGIN PRO STOCK # RV-9908S HIGH PERFORMANCE VALVE SPRINGS.....
FOR 273-318-340-360ci V8 SMALL BLOCK MOPAR-CHRYSLER PRODUCT....
SINGLE WITH DAMPER....
WILL HANDLE CAMS WITH 505 LIFT.....
1.494 DIAMETER....95 # @ 1.650....270 # @ 1.200..COIL BIND 1.085.......
 
Mopar Performance #312-P4452761

Purple Shaft Cam & Lifter Kit
Adv. Duration: .268°/272°
Dur. @ .050'': 228°/231°
Lift: .450''/.455''
Centerline: 110°
Basic RPM: 1500-5800 RPM
 
You should like this:

http://www.geocities.com/alwest_83/318.html

DYNO TESTED 318
The proof is in the dyno testing. This engine really performs well and produces the same power as a high compression 340.

Mid 1980's non roller cam 318, rebuilt with stock crank and rods. Arp rod bolts added when the rods were reconditioned. Crank turned .010"/.010". Flat top cast pistons were used. After the block and heads were milled to true up, a 9.2 to 1 compression was achieved. The heads are the #302 swirl port casting from a 1987 318. The heads have the larger 1.88"/1.60" valves installed, competition valve job and were treated to a full port job. Intake is the Edelbrock Performer. Carb is the Holley #3310 750cfm vacume secondary. Headers are basic fit all 1 5/8" primary tube. Cam is the Mopar Performance P4452761 with .450"/.455"lift , 268/272 duration. timing was set at 35 degrees total for the dyno test.

330 horse power @5750rpm.

How does that sound? The exact motor was also dyno run with 360 heads installed and it produced 290 h.p. @5750 rpm. That shows how port velocity is so important. But...290 h.p. is no slouch for a 318. Most of the same information presented here can be applied to the 273.
back to home page
 
Cams
Well, there are a million cam choices out there. The two I would suggest are the following Mopar Performance cams:

P4452759 .430"/.450" lift, 260/268 duration

P4452761 .450"/.455" lift, 268/272 duration

Both of these cams have a lobe seperation angle(LSA) of 110 and a 108 intake centerline(ICL). The "759" cam was developed to make more torque than the original 340 grind with the same horse power. The "761" cam was developed to make the same torque as the 340 grind but more h.p. Make sure you degree the cam in, very important. The 108 ICL is the installed point the factory suggests. My cam choice would be the "761". It will have a lope idle. Be sure to use a dual chain/gear set and match the valve springs to the cam choice. Either of the above cams can use 340 replacement valve springs or Mopar Performance P4120249.


This is all from that previous link.

Yes those ebay elgins should work for you on the cheap.
 
Does that mean the 340 with the X heads (2.02/1.60 valves) and that cam would produce more power?
 
mopar340dave said:
Cams
Well, there are a million cam choices out there. The two I would suggest are the following Mopar Performance cams:

P4452759 .430"/.450" lift, 260/268 duration

P4452761 .450"/.455" lift, 268/272 duration

Both of these cams have a lobe seperation angle(LSA) of 110 and a 108 intake centerline(ICL). The "759" cam was developed to make more torque than the original 340 grind with the same horse power. The "761" cam was developed to make the same torque as the 340 grind but more h.p. Make sure you degree the cam in, very important. The 108 ICL is the installed point the factory suggests. My cam choice would be the "761". It will have a lope idle. Be sure to use a dual chain/gear set and match the valve springs to the cam choice. Either of the above cams can use 340 replacement valve springs or Mopar Performance P4120249.


This is all from that previous link.

Yes those ebay elgins should work for you on the cheap.
Click to expand...

Did you see my other post, I already have the 761 cam in the motor
 
Yes, that cam you have will work with that Elgin spring I posted and it will make well over 340 HP.
 
I have never seen a 340 make less than 340 hp. I have a factory 69 340 4speed with x heads and bigger cam. This thing makes way over 400 HP.
 
I Have A Set Of New Edelebrocks That Were Run For A 75 Miles Or Less. I Built A New Engine & Changed The Cam. I Changed The Valvesprings To Match The Cam. They Came Off The Eldelbrock Alum Heads. I Would Take $30.00 + Shipping
 
mopar340dave said:
http://cgi.ebay.com/ebaymotors/NEW-...ptZMotorsQ5fCarQ5fTruckQ5fPartsQ5fAccessories

Check these out while I look at some others.
They are Elgins and the price is right.
16 NEW ELGIN PRO STOCK # RV-9908S HIGH PERFORMANCE VALVE SPRINGS.....
FOR 273-318-340-360ci V8 SMALL BLOCK MOPAR-CHRYSLER PRODUCT....
SINGLE WITH DAMPER....
WILL HANDLE CAMS WITH 505 LIFT.....
1.494 DIAMETER....95 # @ 1.650....270 # @ 1.200..COIL BIND 1.085.......
Click to expand...


These are $30, while the Mopar Performance springs are (16x9) $144. I like saving some dough, but are the $30 springs up to the task?

Also regarding the 340 article from comp cams, I am a little confused as to which springs and keepers they used. I'll call them to clarify.
 
I just reread the article and it is more clear as to which springs and retainers they used. Are Elgin and Engle the same manufacturer?
 
These Came Off An Edelbrock Head #60779. They Show That Seat Pressure Is 91-100 Lbs, Installed Height Of 1.65.
 
Engle is in California, Elgin is in Illinois....differnt companies.
The ebay springs are decent and will work for your app.
Mike's are also good and will also work + you to would be doing a green thing by recycling his slightly used parts + you get a bargain in the process.:-D
 
If it was mine......... I'd pull the heads off and get a good 3 angle valve job done, replace the retainers, locks and springs, and have the springs professionally setup and installed so the spring pressures are where they should be. More work, but better result.
 
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