Which Comp. Mags.?
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Joined: Oct 2002
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PN 1305-16
The Pro Mags are fine, very light and strong. The stud is the weak link in the system so the larger the better. A 7/16 is the way to go on everything, even a simple flat tappet 2bbl circle track motor. After the pushrod the weakest link in a standard rocker arm setup is the stud, then the rocker itself.
Bret
The Pro Mags are fine, very light and strong. The stud is the weak link in the system so the larger the better. A 7/16 is the way to go on everything, even a simple flat tappet 2bbl circle track motor. After the pushrod the weakest link in a standard rocker arm setup is the stud, then the rocker itself.
Bret
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Joined: Oct 2002
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The old man will probably put a little more on here but the stud bends when a load is applied against it thru it's movement, the LESS bending (deflection) you have in the system the better the valve will follow the intended path.
Bret
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Joined: Oct 2002
Posts: 2,931
From: Upstate NY
The loads from the pushrod and valvespring are not parallel to the stud centerline. Ergo, there are bending loads as well as tension loads on the stud. These loads deflect the stud and fatigue it...both detrimental to valvetrain control and longevity. If you were to measure the deflection of a 3/8 and a 7/16 stud using the actual dynamic loads experienced by the valvetrain, which are considerably more than just the static loads calculated from springrate/lift, you would see why 7/16 is preferred. The 7/16 stud is about 1/3 stiffer than the 3/8.
For a given length stud, thicker is better. Lots of things in nature work like that.
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Joined: Jun 2006
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Get the nsa pro mags, guideplates which then you need the hardened pushrods, and 7/16 studs. if your going to do it then do it right. and if your going to get a bigger cam down the road sometime, then your going to need the hardened pushrods and the 7/16 studs anyways.
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Joined: Dec 1969
Posts: 27,725
From: Little Rock, AR
You have to remove the studs to put the guideplates on, so going to 7/16" studs should be a no-brainer. I can't think of any reason you would not use 7/16" studs (especially after seeing the advice previously given).
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Joined: Mar 2003
Posts: 1,213
From: Milwaukee, WI
The head is taped for a 7/16" stud right from the factory. The factory stud necks down to 3/8" to accept the stock rockers where the aftermarket is a full 7/16 " diameter. They're cheap and the rockers are the same price so go with the 7/16 pro mags.
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Joined: Oct 2002
Posts: 6,518
Get the nsa pro mags, guideplates which then you need the hardened pushrods, and 7/16 studs. if your going to do it then do it right. and if your going to get a bigger cam down the road sometime, then your going to need the hardened pushrods and the 7/16 studs anyways.
Bret
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Joined: Oct 1998
Posts: 3,144
From: Jackstandican
Yes. For the spring loads/rpm you are running it would be a good idea to get chromoly. Hardened pushrods (at least the ones I've ordered from LPE) worked great for mild profile cams such as the 211 and hotcam with shift points around 6K rpm.
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http://web.camaross.com/forums/showthread.php?t=501667
Long thread but good reading.
Bret
Long thread but good reading.
Originally Posted by Crane Cams
"Most of the time, power flattens out or is lost when “valve train separation” occurs. Again, the biggest culprit in causing this situation is the flex of the pushrod. In our tests at Crane, we have found 12 HP in a 350 Chevy with a 204/214 @ .050 cam (.420/.443 valve lift) just by going from a .065” wall pushrod to a .080” wall pushrod, and the springs were only 110# on the seat and 245# open! "