Pushrod lengthen OR Shim??

AMC has been out of production since 1988 of course and their engines were produced by Chrysler for quite a while, however the same valve train design including the lifters were used from the beginning of AMC V8's up through the end of production and as it happens, "some" mopar lifters are the same and others? Are not but it does pay to be able to recognize which ones are compatible. But the bottom line simply is, the non-adjustable valve train was designed to take advantage of the lifter tolerance so that you can install them and the valves and tighten them down and forget about it. That takes into account rebuilt engines, modified engine and new engines. Bolt them in and tighten them up.
If it was intended that they needed to be adjusted in some way or another the adjustments would have been designed in also.
So as long as you are installing a cam that works with in the tolerance built into the lifters which were supplied from who knows where, but are sold as AMC replacement parts, worrying about adjustments is a non-issue
The rule of thumb used for that was as long as valve lift is less than .5 inches, the non-adjustable valve train will work quite adequately.
That said, it has proven out to be true by both time and many engines. Including all of them I have built.
But
If you feel the need to get creative on adjustments, go for it, that is part of the hobby. Personally I am quite satisfied with the results I have had by bolting things together with out a problem.
As my preference in cams has been Iskenderian for the engines I build, when I order a cam, I also order a set of Iskenderian hydraulic lifters. As their cams and their lifters have worked as I expected them to along with out a failure I guess I am satisfied that I have been using a quality product.

6PakBee wrote: I think this whole issue is becoming convoluted. IMHO there are only two issues here. 1) Lifter preload: I fail to see how differences between lifters matter. The function of a hydraulic lifter is to compensate for thermal growth in the valve train and manufacturing tolerances. If the lifter fits the hole, is compatible with the cam, is adequately supplied with oil, and fits the pushrod used, then the only parameter left is preload. For a street engine I try to shoot for 0.030" between the pushrod socket and the retaining clip. 2) Rocker arm geometry: The height of the rocker arm pivot point is going to determine the contact pattern of the tip of the rocker with respect to the stem of the valve over the travel of the valve. There are a multitude of posts on rocker arm geometry on the forum and I'm not going to waste everybody's time repeating them. Enough to say that the height will affect the geometry. In short, determine the height of the pivot to get the desired geometry and then determine the length of the pushrod to get the desired preload. It's as simple as that.

You are correct. John was just telling the OP to bolt it in and go because the factory designed the tolerances in. My point is that pushrod length will vary depending on lifter height and cam base circle. The OP's cam and lifters are NOT stock and therefore not original AMC. Either a pushrod change or shims will work for him but bolting it on and tightening till it stops is asking for big trouble. I build many AMC engines and always check for proper pre-load. We have one engine at the shop that was built by another shop. They just tightened like the book says. It broke the studs out of the head during break in. The OP is on the rite track. I would get new pushrods. The difference in the stand height will change the geometry a bit but on stock style slider rockers it is not as critical.

Step 1: Remove hydraulic lifters and its cam
Step 2: Install screw in studs
Step 3: Install solid lifter cam
Step 4: Install Solid Lifters
Step 5: Set lash
Step 6: Throw hydraulic lifters as far as you can
Step 7: Never look back ever again