273 stock push rod length?

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Syleng1

Syleng1

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Looking to buy a set of those Mancini 273 look a like adjustable rockers for the 340 with J- heads and I cannot find for the life of me the stock 273 push rod length.

Anyone know for sure? I found a set of stock push rods from Mancic they sell as 7.500" in length but it has been so long I dont want to trust my memory.
Thanks in advance,
Joe
 
adjustable rockers and solid lifters = 7.34", adjustable rockers and hydraulic lifters = 7.25", non adjustable rockers and hydraulic lifters = 7.51"
 
Marcohotrod said:
adjustable rockers and solid lifters = 7.34", adjustable rockers and hydraulic lifters = 7.25", non adjustable rockers and hydraulic lifters = 7.51"
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THank you,

I appreciate the help. I did so badly at Lebanon Valley last Sept for the Mopar Saturday that I've got to make some changes.
 
We had to get custom push rods when we built our 340 with 273 rockers...
 
Best is to measure after heads are on it, I have the MP 557 solid cam and 273 rockers, the stock length 273 solid pushrods were too long. Ended up with some summit pushrods that worked.
 
How much error could be in length of push rod and have the 273 adjustables make up the difference?
 
probably pretty close, like any adjustable rocker, you don't want too much adjuster sticking out the bottom.
 
krazykuda said:
We had to get custom push rods when we built our 340 with 273 rockers...
Click to expand...

Got a part number? I have to come out of pocket for a second set of pushrods and I want to get it right this time, since I could not really afford the first damn set.
 
As long as you don't machine every surface. I replaced my valves. (should have compared the length between new and old) machine seats, (valves sit further in making the stem dimension longer, Mill the heads. (shorter pushrods). I call it tolerance stacking. I had to measure and I did find a set of Summit pushrods that worked with rocker shaft shimming to get the geometry closer.
 
The ones I have are the 7.34 length and they are too long. I do however have the Crane replacement adjusters and nuts, so that might make a difference. Engine is a 360, stock stroke with a hydraulic flat cam. I am certian the 7.25" pushrods will work, but I cannot find any off the shelf. Just my luck.
 
RustyRatRod said:
Got a part number? I have to come out of pocket for a second set of pushrods and I want to get it right this time, since I could not really afford the first damn set.
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You would have to ask @Eddie348 where we got his. They were custom made and reasonably priced (cheaper than some of the off the shelf ones)... And we got them on three days...

The info is in a thread on here somewhere, but I don't know where to find it... It should be somewhere around end of April to mid May last year...

In this picture I compare the stock 273 solid push brod and lifter and convert it to work with the hydraulic lifter... The lifters are not the same dimensions, so you have to adjust for the difference in lifter height.

Pushrod compare 01.jpg



In this model I back it into the lifter length as defined by the push rod manufacturers which is "ball to ball" which comes out to 7.064" from the bottom of the ball in the cup to the bottom of the ball at the other end... Then I also estimated the overall length that you can easily measure with calipers at 7.219"... This is what we used to go with the replacement rocker arm stud with the lock nut (I believe it was the crane replacement rocker studs that you recommended, Rob).


Pushrod Final Spec.jpg
 
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RustyRatRod said:
Got a part number? I have to come out of pocket for a second set of pushrods and I want to get it right this time, since I could not really afford the first damn set.
Click to expand...

We had a hard time trying to find them also. Many companies said that theirs were right, but turned out to be the wrong one...
 
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RustyRatRod said:
I do however have the Crane replacement adjusters and nuts, so that might make a difference.
Click to expand...


Rob, can you list the part number for the crane replacement adjusters and nuts???

That's what we used when we did Eddie's 340. We ended up getting an adjustable pushrod, then putting it in each position 5 times with 1 1/2 threads showing below the rocker arm, then I averaged all 80 readings to get 7.219" overall length... Then did the CAD to find where the bottom of the ball in the cup would be to give the manufacturers the "ball to ball" reading...

Let's get all the info in one thread as many people like to run the stock 273 adjustable rockers on hydraulic cam small blocks...

Then maybe OE Push Rods can assign a part number and can make them available for everyone...
 
WOW!

I had no idea this much information would surface over stock pushrods- You people are GREAT! a bit crazy- but great as I am sure even the factory did not go thru this much energy designing the whole system.
I would love for this thread, after we are all done, could be saved for future questions and answers to save a lot of trouble.
THANK YOU!
Joe
 
gtsdude said:
View attachment 1715018703

This is the set I ended up using, the base circle on the MP 557/296 cam was bigger than my old cam, that was a smaller MP cam, 508/280 solid IIRC
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Yup, that's one of the sets I have here that is wrong. They measure 7.34. If they were the actual advertised measurement, they would be fine.
 
RustyRatRod said:
Yup, that's one of the sets I have here that is wrong. They measure 7.34. If they were the actual advertised measurement, they would be fine.
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I noticed that when I got them, they worked so I never bothered to measure them.
and here I thought I measured wrong.
 
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gtsdude said:
I noticed that when I got them, and here I thought I measured wrong.
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No sir, you surely didn't. I was kinda floored, myself. Now I have two sets of useless pushrods. lol
 
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