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Old 06-19-2008, 12:17 AM
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BBC Rocker Arm Ratio

Is a 1.60 ratio rocker arm a typical size for BBC's?

I just installed a Lunati Voodoo roller cam and matching Beehive springs and noticed that the cam card says .600 lift with 1.6 ratio rocker arms. When looking at the specs for my motor I noticed that I have 1.7's which would put the valve lift at .6375 which is beyond the max lift for the springs at 0.600.

The same springs I have but for .700 lift require a 1.950 installed height which will require machining of my heads (I am assuming b/c a couple are shimmed at .015 to get to 1.88 installed height (most at .030)).

So I figure the cheapest route is to order some 1.6 BBC rockers from Summit. They have 1.4, 1.65, 1.7 and up, no mention of 1.6, so I am lead to believe that 1.6 is not a standard BBC rocker arm ratio.

Any advice or insight on this situation would be appreciated. I will be calling Lunati in the morning to see what their take on the situation is.

Maybe it's a typo. I just looked at the cam card for the cam just below mine and the rocker arm ratio is listed at 1.7. I'm keeping my fingers crossed.

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Old 06-19-2008, 06:19 AM
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How about a few more details ??
Is it the hydraulic roller Voodoo # 60212 ?
If so,according to the online cam card I found at Lunati you are good to go with the 1.7:1 rockers,which happen to be the stock bbc ratio.
Heres a link;
http://www.lunaticamshafts.com/Produ...d=2156&gid=289
If you have any doubts,call Lunati.Proper valve spring selection is the most important peice of the pie when it comes to properly matching your valvetrain.And making absolutely certain that your installed height,open pressure & coil bind are within specs is also necessary.
Guy
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Old 06-19-2008, 06:40 AM
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I just found your other post about valvesprings,I see your cam is # 60622,which I found in Jegs online catalog,but that cam matches up with the one I posted above,# 60212,as I couldnt find # 60622 in Lunati's on line list.If you want to remove any doubts,I will give you the home phone # of the man that designed this line of camshafts,UDHarold Brookshire:

Harold is working for Lunati again and is making new profiles getting in touch with him is hit and miss he posted yesterday that his number is (662) 562-4933.

Tell him that Guy Hiltz from Nova Scotia Canada gave you this info.
He will be able to advise you what to do.
Guy
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Old 06-19-2008, 08:38 AM
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Thanks for the info.

Before I called Lunati this morning I checked the cam card in the garage. I had been looking at one downloaded from summit.

The card downloaded says 1.6 ratio rocker arms.
The card that came in the box says 1.7.

It appears that at one time there was a typo which Lunati has since corrected.

Now I found it on Lunati's site (BBC Mark VI Voodoo). (My brain must have taken a time out last night)
Lunati's info

Summit's Info

I'll let Summit know they need to update this info.

Thanks again
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Old 06-19-2008, 08:48 AM
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Stock rocker arm ratio is 1.7 for bbc's and generally speaking that is how lift is measured. Lobe lift x 1.7= valve lift
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Old 06-19-2008, 09:50 AM
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I see where I was getting confused,I assumed you were talking about a Mark IV bb,although both the # 60622& the 60212 appear to be the same grind.
Guy
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