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I just finished building my 427 tall deck for my 69. I'm using Pro Comp aluminum heads, 1.7 roller rockers, hydraulic lifters, bored .100 over and 454 Eagle crank.
My question/problem is: I adjusted the valve lash properly, I'm using hardened pushrods and guide plates. The rocker rollers are off center on the valve stems side to side of the rockers. The rollers only cover about 2/3rds of the valve stem. Front to back of the rockers they ride nicely through the rotation, open and close the valves just off center both directions.
Is this side to side of center normal for big blocks? I know center is optimal.
The rockers look to be spread apart, that is while looking at the exh and int they are both spread to the outside and both need toed in on the vavle end.

How do I bring these rockers in to center on the valve stems?
Thanks in advance
Jeff Z
 

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Assuming your Valve geometry is correct and push rod length OK and the tip of your roller rocker is not rolling off the top of your valve stem, I take it that you are concerned about centering the side play movement.

Guide plates are supposed to do this but they have to be adjusted to your particular setup. You require a long steel rod and verily heavy maillot. Working on one cylinder as an example. Loosen the rocker Bolts, now torque (whatever 50lbs) only the intake rocker bolt such that the guide plate positions the push rod correctly for the Roller rocker to center on the Valve Stem. You will note that the Exhaust Roller Tip may or may not be centered after you have torqued the Exhaust Rocker Bolt.

Here's the Tip: loosen the Exhaust Rocker Bolt just enough to release the guide plate (do not loosen the intake Rocker Bolt). Using the long steel rod and heavy mallet tap the Guide Plate around the Exhaust Guide Fingers to rotate it around the Rocker Bolt. You might also have to tap the center of the Guide plate to change warp in order to lineup the exhaust fingers of the push rod guides in order to center the roller tips on the valve stems. You are attempting to bend and rotate this portion of the guide around the rocker bolt.

I takes time to adjust all 8 guide plates. When finished MARK each plate as #1 for #1 Cylinder ... etc. Note: torquing the Rocker Bolt can change the angle of the Push Rod Guide enough to misalign the roller on the end of the Valve Stem.

I've seen people cut the Push Rod Guide Plate in half in order to align the Roller Rocker on the Valve Tip, this is particular if you're running off set Mechanical lifters.

Off course the alignment is important to prevent side forces from wearing out your Valve Guides Rocker Bearings ... etc

They don't teach this in school :eek:))
 

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Get yourself some factory stock guide big block plates and you will probably be all set. Many of the aftermarkets just don't quite fit correctly.

Have seen this cure the problem many times by many people.

Harry P. Hunter
 

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I shouldn't say anything, but,, damn these guys are good.
 

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I agree about getting some factory ones.

I have a new set of Eddy ones from their BBC RPM heads I had to throw out. Rockers were all off. I cut them all in half and I was ready to weld them up until A friend of mine brought over a set of factory ones that were 39 yrs old. Guess what? Perfect fit with no tweaking.
 

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I have them so bad that I had to cut the guide plates in two to get the alignment correct. Loosen the studs enough so that you can move the guide plates without a lot of effort (when you move the engine through it's cycles keep an eye on the guide plates so they don't move) It's exceptable to grind the rocker stud holes so that the guide plates can move enough to get the alignment correct. Make sure you get the alignment perfect it really helps keep the valve train alive.
 

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you know all these after market heads will not be a perfect fit. I read all the crap on the cheap heads out there and it's not buyer beware but be ready to modify what you bought! You want to be a owner of something great, well you have to use common sense and you know what they say! you get what you pay for!!!!!!!!!!
I too Bought some good aluminum heads a while back and they are machined a little bit better but if I can save 2,000 and do a little clean up. Well it's worth the effort to buy these wonder cheap heads and modify the guide plates or try different brands if the stock ones don't work well. And by the way? most of you will have someone that has a old set of heads and guess what they will have those guide plates on them that you probably need! so go make friends and save the headache of worry. I just bought a set of PRO COMP stage II heads from skip white in Tenn. Remember buy heads from a known machine shop, they will honor their products if there is something wrong and they will fix the problem......
P.S. remember to check that the rocker rides in the center of that valve tip! ere's a link for correct pushrod length , read it all!
http://www.carcraft.com/techarticles/116_0401_setting_pushrod_length/index1.html
 
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