Has anyone used this cam with stock heads? What stock diameter springs should I use? I dont want to machine the heads for bigger springs.Also do you think this spring will pull out the studs? GM part# 3927142 110#1.70" and the average rate pounds per inch 358

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89 350 TPI,edelbrock intake,SLP headers,highflo cats,flomaster cat back,accel 300+ ign,ported plenum and runners,ported maf,auto w/shiftkit,cold air induction,AFPR,Ed wright chip,3.23 posie

 

E-man,

Unless you are going to use tapered valve springs or want frequently broken springs, you'll almost have to machine the heads for a larger diameter spring. I searched all the manufacturers I could find for 1.250" springs that would tolerate the lift of an LT4 "hot" cam, and nothing was available except the tapered or conical springs. Even some of the oval wire springs offered by some aftermarketers were a larger diamter. The GM LT4 springs are oval wire, and measure at 1.342" O.D., requiring light machining.

I would also strongly recommend screwed studs with any cam over 0.475" lifts used at higher RPM or under "severe duty". A set of screwed studs can cost less than $20.00, and installation takes about a few hours on the garage workbench if you're careful. The old studs generally remove very easily (so easily that it's easy to see why they pull out), and tapping the holes is not difficult if you have the correct guide. You'll sleep better knowing you have the right springs and studs.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

Thanks vader thats what I thought.

 

E-man,if I read your post correctly,you want to install a ZZ4 cam.The ZZ4 and the ZZ3 cams are the same,but the ZZ4 crate engine comes with LT4 springs,although the ZZ3 came with ZZ3 springs(part#10134358)that have a 1.273 diameter that fit(at least in my case)in the spring seats of the L98 heads.

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We need Perry Mason

 

I used Manley 1.25" springs on my L98/ZZ3 heads with the ZZ4 cam.

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I was looking at the 1.273 springs.But the guy I was talking to at jim pace GM performance parts said the springs might pull the stock rocker studs out with the .510 lift.Also GM dosn't give a open pressure just a average rate pounds per inch for the springs in the catalog.If someone knows the open pressure of the #1013458 springs maybe I can find something a little less that might work.What is the open and closed pressure of the manley springs? I was also thinking about two other cams if the ZZ3 didnt work a comp cams grind lift I.480 E.480 /duration I210 E220------crane cam grind lift I.452 E.465 /duration I214 E220.What do you guys think ZZ3/comp/crane??

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89 350 TPI,edelbrock intake,SLP headers,highflo cats,flomaster cat back,accel 300+ ign,ported plenum and runners,ported maf,auto w/shiftkit,cold air induction,AFPR,Ed wright chip,3.23 posie

[This message has been edited by e-man (edited September 27, 2000).]

[This message has been edited by e-man (edited September 27, 2000).]

 

somebody????

 

I have a ZZ4 that has never been installed, I am going to replace the ZZ4 cam with compcam 8-302-8. I call compcams and they said it will work OK. In chevy's perforance cat. they list the spring and gives the ft.# rating.

 

The comp 08-302-8 is same one I was talking about above.Heard anything good about it?

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89 350 TPI,edelbrock intake,SLP headers,highflo cats,flomaster cat back,accel 300+ ign,ported plenum and runners,ported maf,auto w/shiftkit,cold air induction,AFPR,Ed wright chip,3.23 posie