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By 1946international - Last Year
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I have a small collection of Y block parts and engines and noticed that in that pile I have two different length pushrods. The motors these came from were a '57 T bird motor, a '59 or '60 "car" motor and a '60's truck motor that has been rebuilt and may not have the stock parts. So what is the correct length pushrod for which motor? Some are about 8.125" overall and some are 8.258" long. I know these stock pushrods are weak and should be replaced and I see the two different lengths sold just don't know which to buy. I'm building the '57 T bird motor with "G" heads and high ratio rockers. Any difference in the ball or socket size?
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By 55blacktie - Last Year
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54-55 and 60-64 pushrod length is 8.320. 56-59 is 8.125. The big-valve G, 471, and 113 heads use the shorter pushrods; all others use the longer pushrods. Keep in mind that this applies to stock configuration. All are 5/16 diameter.
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By paul2748 - Last Year
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You have to look at cup size. Some aftermarket pushrods have a cup size that is too small for the ball so the pressure is centered on the sides rather than the bottom of the cup. This can result in a broken cup.
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By 1946international - Last Year
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Thanks for the info, I have mocked up both the short and longer pushrods on a spare motor I have and was able to adjust the valves correctly with either. Is there a down side to use the longer pushrods with a "G" head if correct adjustment can be made?
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By KULTULZ - Last Year
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' I have mocked up both the short and longer pushrods on a spare motor I have and was able to adjust the valves correctly with either. Is there a down side to use the longer pushrods with a "G" head if correct adjustment can be made?'
I would think that with all of the valve-train changes over the production years (rocker arm ratio - differing push-rod lengths) that one would want to confirm correct valve-train geometry before final assembly, possibly especially with an aluminum cyl head.
SAVED SERVICE NOTE -
"Apparently, there aresome problems with the compatibility of some aftermarket parts & Ford Rocker Adjusters. John Mummert says factory adjusters have .360" diameter balls & there should be 0.010 - 0.015"clearance in the push-rod cup. No clearance for oil will result in failures."
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By 55blacktie - Last Year
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Thanks for the info. I'll keep that in mind, if I need to buy custom-length pushrods.
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By charliemccraney - Last Year
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A longer pushrod moves the adjuster screw ball end closer to the rocker arm, which provides a slight increase to the ratio. If you have the option, use the longer pushrod.
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By KULTULZ - Last Year
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Here 'ya go. MR. TED EATON has a TECH ARTICLE on arriving at correct geometry (along with others).
https://www.eatonbalancing.com/2007/12/10/rocker-arm-geometry/
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By 1946international - Last Year
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Kultulz, I read that yesterday also Ted has another article titled ALTERING ROCKER ARM RATIO BY USING DIFFERENT LENGTH PUSHRODS or something like that, and the conclusion is what Charlie said above, If you can use the longer pushrods, use them. So I think that is what I will do. And as I understand it, the ball size is the same except on some aftermarket pushrods that are made incorrectly.
Thanks for the help
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By 55blacktie - Last Year
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Whenever using different length pushrods/rocker arms, milling heads/block, you should check rocker-arm-to-valve-tip alignment. Ideally, the adjusters should be midway when properly aligned.
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