Push Rods


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By 1946international - 4 Years Ago
While I was cleaning up the parts for my 292 build, I noticed that I have two different length push rods. What I'm doing is cleaning up the parts from two motors and picking the best to use in this build so I have two complete sets. My question is, should I use the longer or the shorter and why the difference? One motor is a '57 T bird and the other was a '59 mid size truck motor.
By 1946international - 4 Years Ago
I ran into an article by Ted, from his website that talked about rocker geometry. it sounded like it is somewhat trial and error as you just use the pushrod that keeps the tip of the rocker in one place in the valve stem. Some of the things that can effect this are cutting the head, decking the block, rocker shaft height, but the thing that sounds like effects it the most is cam base circle, the base circle on a high lift cam will be smaller and will let the rocker ride lower when the valve is closed. I guess the removal of the oil deflectors that were installed under the rocker shaft mounting blocks would make a difference. How about the low or high ratio rockers? Are the long or short pushrods made for either the high or low rockers?    If I'm off base with this or anyone has any other input please chime in.



By one piece at a time - 4 Years Ago
Here is my two cents worth and that is all it’s worth. It has been a while since I investigated the same issue you have.as I recall John Mummert site list two or three different pushrod lengths depending upon what cylinder heads you have.check it out. If your motor is stock you will be OK if modified I suggest getting professional advice such as Ted or John Mummert or Tim McMaster. I also recommend new pushrods as they are generally stronger and bigger than stock, less likely to bend or break.
By 1946international - 4 Years Ago
Thanks, the only real mod to this motor will be the cam. I don't know what I will go for but it will have just a little more lift to it. So yes, I have heard that these push rods are not the strongest But I'm running stock type push rods in the other 292 that is in the car now and they have held in there for over 11,000 miles, the cam in that motor is close to what I will run in this motor. If I don't get a good answer by the time the motor gets together I will have to reach out to Ted, John or Tim, thanks.
By charliemccraney - 4 Years Ago
Use the length that puts the adjusters closest to the middle of their travel.
By Florida_Phil - 4 Years Ago
Removing the baffles changes the geometry.   New push rods are worth the investment.  I have a box of bent and broken stock push rods to prove it.  I found them in engines I disassembled laying in the lifter galley
By paul2748 - 4 Years Ago
This has come up before but some of the cups on the replacement push rods are smaller than stock so the adjuster rides part way down on the rim of the cup, not the bottom and can result in broken cups.  Check your adjuster against the cup of what ever replacement push rod you use.
By 1946international - 4 Years Ago
charliemccraney (7/8/2020)
Use the length that puts the adjusters closest to the middle of their travel.


Thanks, That is what I needed!

By 1946international - 4 Years Ago
Florida_Phil (7/8/2020)
Removing the baffles changes the geometry.   New push rods are worth the investment.  I have a box of bent and broken stock push rods to prove it.  I found them in engines I disassembled laying in the lifter galley



Thanks, I have read the stock ones were weak
By 1946international - 4 Years Ago
paul2748 (7/8/2020)
This has come up before but some of the cups on the replacement push rods are smaller than stock so the adjuster rides part way down on the rim of the cup, not the bottom and can result in broken cups.  Check your adjuster against the cup of what ever replacement push rod you use.




I have not heard that before, thanks for the tip
By Ted - 4 Years Ago
See if this link to John Mummert’s site helps.
http://www.ford-y-block.com/rockerarm.htm
By 1946international - 4 Years Ago

PART#         ROCKER ARM RATIO                  VALVE DIAMETER                    PUSH ROD LENGTH (Effective)

EAN                54-55 jamb nut     1.43:1                EXHAUST all 1.51"                1954-55 3/16" radius ball 8.11"

ECG 6564     56 jamb nut            1.54:1                INTAKE 1954 1.64"              1956-59  3/16" radius ball 7.98"

ECG 6564    57 self locking      1.54:1                 INTAKE 1955-56 1.78"        1960-64  3/16" radius ball 8.11"

5751066      58-64 self locking 1.43:1                INTAKE 1957-59 1.93"

                                                                                    INTAKE 1960-64 1.64"
as always, thanks Ted.
the above is clipped from that site, so it looks like the rocker style (with or without the self locking feature) makes the difference, weather you use the longer or shorter push rod. Assuming all the valves are the same length, as the exhaust valves are all the 1.51" and this does not recommend different push rods for intake or exhaust I guess this would be the case. So according to this, it looks like I would use the longer ones.