273 rockers on 340 with hydraulic cam

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Mtrhead

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Hello recently acquired a set of 273 rockers ,I want to install them on a hydraulic cam 340 and plan on getting pushrod length checked for the right length pushrod...but my question is the set of rockers I acquired came with shims(cupped washers)...what is the reason for the shims?...is this an old trick to use on hydraulic cam?...just curious..I'm probably not even gonna keep the shafts because they don't have banana groves and I wanted hard chrome ones like rocket has...or do I need...should I modify mine with grooves?..thanks any advice is appreciated, Will

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I don't see any cupped washers, unless you mean the washers on the mounting bolts; In which case, those are sometimes used for geometry correction. But as you may have noticed, those rocker's need matching pushrods.

Going back to the cupped washers, if they are ordinary washers, with the same thickness in every direction, then they are some-one's bandaid and should Not be reused, because they cannot simultaneously fit both the saddles and the shafts and so they are somewhat unstable in the lateral direction. And very possibly the tiny bolts will fatigue and possibly come loose under the bending forces, that may come with much more than 318-type valve springs.
There are proper washers and Geometry kits to fix geometry errors, which in the Mopar camp, are common..
 
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Looking at the photo- I’ve never seen the top curved washer used on the bottom like that before. Maybe remove those as they are going to slow or stop oil flow to the shafts.
 
What AJ said..... Correct shaft shims cross section would have a banana shape, if you will.
 
Hello recently acquired a set of 273 rockers ,I want to install them on a hydraulic cam 340 and plan on getting pushrod length checked for the right length pushrod...but my question is the set of rockers I acquired came with shims(cupped washers)...what is the reason for the shims?...is this an old trick to use on hydraulic cam?...just curious..I'm probably not even gonna keep the shafts because they don't have banana groves and I wanted hard chrome ones like rocket has...or do I need...should I modify mine with grooves?..thanks any advice is appreciated, Will

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You really don't need them
 
But why are they there and what were they used for
 
Crane used to make a specific pushrods for that application.
 
That's exactly what I was thinking somebody had this setup on a hydraulic cam
 
I'm going to use a push rod Checker and then make some pushrods out of some Slant six push rods the correct length
 
Sum-G6420 Is what you want. Somebody built that shim (washer) to run them on hydraulic cam but I think you would need twice that distance.
 
So Sum-G6420 is the pushrod needed and I can ditch the washers?
 
Was an eBay deal... I tried that and they didn't even know anything about them they were on an estate sale..price was right!!
 
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