I am getting a cam grind done at Clive Cams here in Australia and he has suggested a valve spring rate of 95 seated and 220 open or thereabouts .
Does anyone know of any brands with a rate close enough to this ?
Cheers,
Greg

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Greg,

Can you post the cam specs?

It sounds like stock Mopar 340 V8 valve springs would drop right in and work for you.

Lou

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Home of Slant6-powered fun machines since 1988

Lou , I don't have the cam or cam card yet but he told me it is a 160 grind at 114 profile .
I guess the 160 is his part number for a specific grind .
It is to suit a supercharger running low PSI.

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I found these 2 part numbers at Rock Auto

http://www.rockauto.com/en/moreinfo.php ... cc=1079647

http://www.rockauto.com/en/moreinfo.php ... 28&jsn=606











The pressures are close to what has been recommended , which one do you suggest ?

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A valve spring for a boosted motor needs to be stiffer, then for a non boosted engine with similar cam specs. A 1.44 dia intake valve with 20 psi boost will have 32 lbs less effective seat pressure then the same spring with zero psi boost.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

A valve spring for a boosted motor needs to be stiffer, then for a non boosted engine with similar cam specs.
A 1.44 dia intake valve with 20 psi boost will have 32 lbs less effective seat pressure then the same spring with zero psi boost.
A 1.5 intake valve will have 35 lbs less effective seat pressure, at 20 lbs boost.
A 1.6 intake valve would be 40 lbs less at 20 lbs boost.
The larger the valve, and the more the boost, the greater on seat pressure is needed.

Just using some numbers to show effect. Find the area of the valve head, (radius squared, times pi (3.14)) minus area of the stem, times boost.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Well I'll be!!! I never thought of that but it makes perfect sense! Learn something new every day.

Rick

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2 Mopars come with Spark plug tubes. One is a world class, racing machine. The other is a 426 CI. boat anchor!

12.70 @ 104.6

Thanks blokes , will see what i can come up with .

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