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By repeater - 7 Years Ago
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Ok, I think I'm confusing myself a bit here. Getting ready to build a 292 and I have a set of G and 113 heads that I can use on it. Planning on using a mild cam. I do not, however, have a set of higher ratio rockers that came on these heads originally. I do have several sets of rockers that came off of C0TE heads, which are the 1.43 ratio. Should I attempt to source 1.54 rockers, or just use the 1.43's? If I use the 1.43's, do I use the longer 60-64 pushrods? If I use the 1.54's, I assume I use the shorter 56-59 pushrods? Does it matter since they can be adjusted? What's the best option?
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By miker - 7 Years Ago
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You need to look at the cam specs. If the cam you want is measured at the 1:54's, then the effective (at the valve) lift and duration will be less with the 1:43's. The cam specs can compensate for that, but figuring it out will take some work.
Probably the best bet is to go to a y block guru, Eaton and Mummert come to mind, ask for their recommendation, and order the cam.
As to the push rod length, the best is to measure it with an adjustable rod for the proper geometry, and order to that length. But a good builder will know what's right if you know how much the block and heads have been decked and milled.
One other thing, and I'll probably get scorched for this (we don't flame each other much here), is remember our motors tend to have more stoke and smaller bores than the other motor. So the torque numbers are better. So don't let your scrubbie buddy pick the cam.
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By charliemccraney - 7 Years Ago
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The pushrods you need depend on the heads used, not the rocker arms. Long for 54,55 and 60-64. Short for 56-59.
http://www.ford-y-block.com/valvetrain.htm
Rocker geometry is more complex than pushrod length with shaft mounted rockers. Heavy milling or larger than stock cams make this more important.
http://www.eatonbalancing.com/2007/12/10/rocker-arm-geometry/
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By repeater - 7 Years Ago
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charliemccraney (4/18/2017)
The pushrods you need depend on the heads used, not the rocker arms. Long for 54,55 and 60-64. Short for 56-59.
I was under the impression that the heads were all the same in terms of rocker mounting placement, that the rocker arm ratio between the 56-59 were different, or maybe I'm misunderstanding that?
Also, I noticed Mummert's rocker stands be flipped for "0.050"....I assume this is just to help gain the correct geometry without having to machine the stands?
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By charliemccraney - 7 Years Ago
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No, there is a difference in the heads as '56 - '59 use the same pushrod and came with both ratios.
You have to shim or machine the stands, depending on how everything works out. Mummert's stands can help get the geometry closer to where it needs to be but they will not correct it in every instance by themselves. The rocker ratio, cam, and milling come into play with that and can require quite a large change to correct.
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By repeater - 7 Years Ago
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[quote]charliemccraney (4/18/2017)
No, there is a difference in the heads as '56 - '59 use the same pushrod and came with both ratios. You have to shim or machine the stands, depending on how everything works out. Mummert's stands can help get the geometry closer to where it needs to be but they will not correct it in every instance by themselves. The rocker ratio, cam, and milling come into play with that and can require quite a large change to correct.
Interesting. I assume they just machined the stand bosses on the heads differently to accommodate for different cam configurations over the years?
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By repeater - 7 Years Ago
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Another questions for folks....what is the consensus on roller rockers at this point, and who's making the best ones to use? I noticed quite a lot of Harlan Sharp's being used, but when I search their site, I'm not finding anything Y block - or are people somehow using the FE rockers?
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By charliemccraney - 7 Years Ago
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Harland Sharp are the best for OEM heads. They make a Y-Block specific rocker.
They are expensive, probably not worth the relatively small gains for the price for most people. Probably about $700 for complete rocker assemblies.
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