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Discussion Starter #1
Having a heck of a time working out the roller rocker tip movement across valve tip. The roller starts just short of center to the intake side and rolls out to the exhaust side too much. I need to go shorter on the push rod to get the roller to start more towards intake but any shorter and the rocker hits the stud nut! I need to find a rocker that has less lower mass so it can go lower on the stud. Maybe some comp cams steel will have more clearance at the bottom. Anyone else had this sort of trial and tribulation with roller rockers?
 

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351W (assuming)? Did you machine the pedestals down for the studs? You generally need to do this for the reason you are citing.
 

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+1 also take into account thickness of any guide plates.....what ratio are the rockers?
 

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Discussion Starter #4
1.6 ratio rockers. The heads are aluminum and came set up with guide plates and screw in studs. I stopped by the local speed shop tonight and bought some Comp cams rockers. In comparing them in store to what I had I think the prob is over. After supper I will know for sure when I get to the shop.
 

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The heads are aluminum and came set up with guide plates and screw in studs.
Never assume they were done right. May not be the problem, but it always pays to double check stuff set up elsewhere and mailed.
Just sayin'.
 

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Hmmm - I'd be surprised if the rockers would solve it, but on the surface everything "sounds" like you shoulda been close to bolt on? Whats the story on the heads - brand/used/mods? What lenght PR's are you using?....
 

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Discussion Starter #7 (Edited)
walla! Comp cams gold series fixed it right up. Easily obtained the center run on the valve stem for the rocker tip. So what did I learn from this? do not buy that cheap proform crap from summit racing!

Anyhow with using the checking pushrod it looks like the 8.150 length is ideal.
 

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HUH! What's the diff on the rockers then? Just curious - the bases of the fulcrums must be thicker or something..? Glad it worked out! You are on the home stretch now!
 

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Discussion Starter #11
So here is the deal. I could not get the proform low enough on the stud to make the pushrod short enough to work because the rocker would bottom on the stud nut. The comps are an easy .1 off the stud nut with perfect centering. The proform roller tip from center of the stud pivot is about 1.8 inches. The comp cams is about 1.69. Now one would think that would throw the ratio off but the ratio is also established by pushrod placement and the pivot point. Another observation is the comp cams is much beefier than the proform in the aluminum. The pivot pin diameter on the proform is about .45 and on the comp about .55. The Comp cams is just a better made and better fitting rocker.
2011-04-12_18-58-44_96.jpg 2011-04-12_19-01-32_537.jpg 2011-04-12_19-04-34_383.jpg
 

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AND the gold ones are just prettier! ;>) wow - it's quite a bit beefier then. Intersesting stare and compare - thanks! Now I know what to avoid next build.
 

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Comp Cams Golds are what I always use in my builds. Good price and simply good quality gear. I have two sets here waiting for engines.
 

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hi,
I'm wondering if you you had the same proform rocker arms in the beginning? Proform 66911
Also, which cylinder heads and cams and lifters are you using?

I'm having are really hard time figuring out the PR length on my 351w rebuild.

I initially used my stock PR which caused one of the lifters to break apart and wore out the cam.
 

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Discussion Starter #16
Same proform. Comp cams 284 xh. Procomp heads. As I stated in the write up as soon as I set the Comp Cams gold on the rockers studs everything lined up perfectly with no messing around.
 

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SO if my math is correct you need to run 8.040 length since the difference on the comp cams and proform rockers is about .11 (deduct from 8.150) or just go with the beefier comp cams rockers....and pass off those pro forms to some poor guy on ebay! ;>)
 

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Discussion Starter #18
Not sure about the math part but I could not get the proform to be in the center third of the valve tip. The best I could get was to start towards one edge and roll across the tip to end up on the other edge. I used two different adjustable push rods and even tried the proform on some cast iron heads I have with the scew in stud set up. When I put the golds on, it was instantly obvious they would work and within a couple minutes 8.150 was the size.
 

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ProForm,just another example of inferior offshore parts. And to think some of us are chastised for wanting the better parts after questioning the foreign stuff.
 

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Yeah, like everything else - "Ya gets what ya pays for!" you can spend hours trying to make inferior work, or spend $ and make your life easier....
 
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