GM calls for self-aligning roller rocker arms on the vortec 350 heads. Why is this? If I were to use guideplates and screw in studs would the self-aligning still be necessary?
Thanks,
Craig

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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com

 

They aren't needed if you use guideplates. The reason for the self aligning rockers is the hole where the pushrod goes up thru the head is bigger on new heads. It doesn't center the rocker on the valve, so the rocker has ridges on it to get the same effect. Don't use them both, though. They try to center the rocker in slightly different places, and cause premature wear.

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Jeff

'85 Berlinetta, Special Beater Edition
Mods include a 4bolt 350 with 280*, .460 lift cam, Vortec heads, Comp Cams roller tip rockers, Edelbrock TES headers, no other exhaust . Also, rusted parts on all 4 corners, and crumpled fenders, thanks to the previous owner.

 

You actually can use the self aligning rockers with guideplates.... Actually if you order rockers for the earlier models from GM, they will send you the self aligners. The standard size has been discontinued by GM anyway.

They're not required though with guidleplates .

 

I also heard not to use self aligning rockers with guideplates. It makes sense. The rockers will try to center themselves over the valve while the guideplate also tries to locate the pushrod. Unless you have them both centered perfectly, either the pushrod will be forced to rub on the guideplate or the rocker arm will not be perfectly centered, a little problem that could cause a big problem at around 6000 rpm.

 

If you're going to have screw in studs, anyways, I'd just get the guideplates, too. I'm not sure why GM discontinued the old rockers. I would take a chance on it. I got the Comp Cams roller tip rockers, and the self alligning ones aren't much more.

 

Thanks for the input guys!

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84 Z28 305HO, 5spd, 222,000 miles, Edelbrock intake, Hedman headers, low restriction exh(w/cat), K&N air filter, 14.630 at 93.17mph
Del-A-lum front control arm bushings, Moog ball-joints, Energy suspension front sway bar end links, Moog rear sway bar end links, Eibach pro-kit springs, tokico shocks/struts, AU secondary rods
www.indycamaro.com