# whats a good set of valve springs to use?



## wytnyt (May 17, 2008)

im rebuilding my matching numbers 400 335 hp engine and am wanting to decide the best set of valve springs to use in my build.
im told the heads are the heart of a good rebuild so im sure you guys can help me out on this.
the block will be .30 over and .10 on the crank
stock pistons
a hi perf cam but not an erratic one
i have a muncie m-20 with a posi 3.23 rear
whats would be recommended on a good set of valve springs to use?
any ideas is most appreciated


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## geeteeohguy (Feb 2, 2008)

If your block is .030 over, you'll need .030 over pistons. If your running the stock 670 heads, you'll have about 10.75:1 compression, so you'll need to run 98--100 octane gas. The alternative is aftermarket heads, factory low compression heads (1971 and later), or best option, dished Ross pistons. I've had good luck with TRW valve springs. The cam company that supplied your cam may have springs recommended for use with that particular cam. Good luck.
Jeff


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## wytnyt (May 17, 2008)

i meant stock as in nothing hi perf.
it will have the cam used in the 360 hp 400 engines.
i know ill need higher octane as its matching 670 heads but am having work done to the heads to handle unleaded fuel.
would i be just as good staying with stock valve springs?


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## geeteeohguy (Feb 2, 2008)

If the stock valve springs check out ok, I would use them for sure. OEM parts seem to be the best in quality.


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## Rukee (Feb 8, 2007)

geeteeohguy said:


> If the stock valve springs check out ok, I would use them for sure. OEM parts seem to be the best in quality.


:agree
If you haven`t bought them yet I`d pop for the forged pistons and have the rotating assembly balanced.


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## wytnyt (May 17, 2008)

Rukee said:


> :agree
> If you haven`t bought them yet I`d pop for the forged pistons and have the rotating assembly balanced.


i had thought about them but the money issue and not sure how much performance they would offer me either


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## Rukee (Feb 8, 2007)

They don`t offer anymore performance, but they are like ten times stronger then the cast ones. The guys who had my car before I did kept rebuilding the motor with cast pistons and kept blowing the motor up. I have a piston here I took out has the ring lands broke between the first, second and third ring. Because the top ring was still intact it passed a compression test, but smoked like heck after it was warmed up.
As far as valve springs go, contact the cam manufacturer and go with the springs they recommend for your cam.


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