Valve Springs

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zmarty27

zmarty27

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Hey gang,

I'm to a point where there isn't much more to do on the ride. It sounds healthy, drives healthy. My interest now is merely splitting hairs. I'm a bit bored and I also don't want to spend a kidney's worth of money. I've stumbled upon a few mentions of using different valve springs aside from the stock. I have a 225 from '74. Is there any performance improvement from using different springs from larger engines? Just a curiosity.

Thanks,
Zach
 
Factory 340 springs bolt right in. Now, whether they would benefit a stock-cammed slant six is another matter. Maybe if your original slant six springs are really weak. I put used 340 springs in my slant, but it has a mild (252 degree) Comp Cam. Probably more spring than I really needed, but they were free.
 
Do you have a Stock Camshaft?

If so, you are fine using the stock springs that are on it
unless they hare old and have lost tension.

I have an inexpensive valve spring tester but I do not know
enough about the slant 6 rocker design to know if it would work
for you.
 
The springs (and their tension) are determined by the aggressiveness of the camshaft profile and stability of the valvetrain as a whole. All else remaining the same, camshaft, rocker gear, lifters, and valves, you will see no performance increase by simply changing the springs. Unless you are solving a problem like valve float because the current springs are worn.
 
If your springs are still good, leave them. If you want to improve your high rpm operation, go with a bee hive spring. But with a stock cam I see little benefit from it.
 
I went with 318 springs in mine, I'm running what used to be called an "RV cam" in my /6.
I've seen it in valve component catalogs where they "call for" the same spring for a /6 as a 318 any more.
 
If you're running the stock camshaft, no need to upgrade springs.
 
Just a FYI. I don't know what year, if at all, it changed, but. Back in the 1960's and 70's the slant spring and the 318 spring were different as installed new from the factory. If you ordered "replacement" slant six springs from the dealer you got the 318 springs. Unless you are having a problem caused by your stock springs, changing the springs will not make any performance improvement.
 
Charrlie_S said:
As near as I can tell, that is nothing more than the 340 spring with a "P" number and at a premium price. Mopar did that a lot. Taking a stock/standard part, giving it a "P" number and raising the price.
Click to expand...

It is the 340 spring. In the Direct Connection days they lowered the price. Not sure today.
 
Aftermarket 340 springs are available for between $5.00 and $9.00 ea. The "P" part spring are about $14.00 each. More than double the price.
 
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