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Im getting ready to install my new Edelbrock E-Street heads and valvetrain on my freshly machined block. The heads,cam, springs, valves, lifters, and pushrods all came in a kit meant to work together, and I plan to reuse the factory rockers. The problem is that the block deck did have some machine work and now that I'm getting ready to install the heads and valve train I realized that the work on the block may effect things. I called the machine shop that did the work and they said that there wasn't much taken off the block and that everything should still work together, but I should still check to make sure. I,m just wondering what the easiest method for doing this is? Ive watched some videos and done some reading. At this point I figured that I would put everything together and try the marker on the valve stem trick and just see where everything is riding. Unless anyone has a better method.
 

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I bought some lightweight springs and an adjustable pushrod all made by comp cams for this purpose. You pull the heavy springs on one of cylinders on the head and replace with the light springs. Install the head on the block with cam installed and then use the adjustable pushrod to make minor changes to the length. Mark the top of the valve with a whiteboard marker, place the rocker rocker arm and rotate the engine a few times. Remove the rocker and observe the wear pattern. The springs and adjustable rod cost me around $30 and are a good insurance that you have the right length rods for your set up, so you don't get unwanted interference between the valve and piston as well as insuring that you engine runs the best.
 

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Something like this.....Comps PR kit includes an adjustable pushrod.It has a very fine adjustment. Ideally you want the "wear" or "witness" marks to be centered and approx. .070 width. At least this is what I was shooting for, based on my learning. If the "witness" mark is toward the exhaust, you need to shorten the PR a "tad", if biased toward the intake, ya need to lengthen it a "tad".Although this exercise seems laborious, there is a great satisfaction derived in knowing how to do this and it guarantees,your engine's performance from the cam's events will benefit from this "blueprinting" exercise. I put this in the same category with decreeing a cam, finding exact TDC, etc. Once you pin down the length (based on the adjustable PR) then you can order your "hardened" PRs.
 

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I would recommend also checking piston to valve clearance, not sure what cam you are using. But I also did the marker way and I also did it this way:


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As others have said, adjustable pushrod and the marker on the valve stem. When I changed heads to AFR165 I used the modeling clay in the cylinder to verify valve clearance.
 

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I measured mine the same way in which My289 posted in the video above. And also a good idea to check piston to valve clearance.
 

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Discussion Starter #7
I would recommend also checking piston to valve clearance, not sure what cam you are using. But I also did the marker way and I also did it this way:


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Would this method work with stock type rocker arms? Where would I measure from. He uses the center of the berings in the video.
 

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Would this method work with stock type rocker arms? Where would I measure from. He uses the center of the berings in the video.
In your situation, you should use the checking spring method. It’s not difficult and will yield the same results.
 

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Ok, dumb question: If the intake/exhaust lift on the cam specs are different, will they still have the same length pushrods? If the answer is yes, which one do you use to determine the pushrod length?
 

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Ok, dumb question: If the intake/exhaust lift on the cam specs are different, will they still have the same length pushrods? If the answer is yes, which one do you use to determine the pushrod length?
Most cams have a minimal difference in valve lift, .020" ~ .030". That much won't make any real difference in the pushrod length, as they typically come in certain increments, Trend does them in .025". Obviously, check both before ordering.
 

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Ok, dumb question: If the intake/exhaust lift on the cam specs are different, will they still have the same length pushrods? If the answer is yes, which one do you use to determine the pushrod length?
Yes. Either. Lift isn't the issue. Having the rocker arm mid-way across the valve tip at 50% of lift with the rocker arm perpendicular to the rocker stud is....
 
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