ok here's the deal the 5.7 TPI motor i'm putting together will have have a LT1 cam and 1'6 RR's that comes out to about .497 lift.my valve springs are from CraneCams and are good up to a .600 lift.i have a set of Crane Cams 1.6 aluminuim RR's.CraneCams states in there instructions they don't recamend you using these RR's with anything higher than a .510 lift.my heads(WorldProducts)will except up to a .520 lift with out being machined
now my question is do i run the risk of breaking RR's with these springs?

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1991 banditt2 #130 of 600
Project 350 TPI Banditt II
http://www.street-dawg-racing.cityslide.com
http://discussion-board.com/GreaterC...dyAssociation/
http://www.cincyspeed.com/

 

Bandit,

I'd be concerned more about the rocker clearances than the spring pressure. Check the geometry and clearances of the system. Check the push rod guide holes for clearance, the undersides of the rockers at the valve spring reatiners, and the slot length of the rockers. The slot length is likely where Crane gets their restriction, and elongating the slot on an aluminum rocker can cause weakness at the fulcrum point. (One reason I like the Comp Pro Magnums.)

Make sure the push rods are sized to allow correct placement of the rockers to make full use of the slot length. The correct placement is when the rocker push rod end and valve roller tip are perpendicular to the mounting stud at 30-33% of maximum valve lift:



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Later,
Vader
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"Let the bodies hit the floor!"
Adobe Acrobat Reader

 

thanks for the info Vader that will be very helpful.so you are saying i shouldn't be worried about the spring pressure?kool that's what i was hoping to hear.

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1991 banditt2 #130 of 600
Project 350 TPI Banditt II
http://www.street-dawg-racing.cityslide.com
http://discussion-board.com/GreaterC...dyAssociation/
http://www.cincyspeed.com/

 

You should still have about 100-110 lbs of seat pressure and mid 300's lbs over the nose for that cam.