Funny how the mind plays tricks.  My comment was based on a memory re: a (supposed) tech article from years back that dealt with increased adj. ball/cup wear due to setting the adjuster/PR length for max. rocker ratio, but a thorough search of all my accumulated literature proved fruitless. So, must be a figment of my imagination.  Search did point out though how complicated are the complex myriad of factors involved re: the compromises between perfect geometry/min. wear, and power range (as Ted’s single comment re: sacrificing guide wear demonstrates). 
BTW: Re: the OP’s original question: I noticed a tech comment (while searching) that stated increasing cam lift typically requires milling (not shimming) the stands (likely in relation to otherwise OEM setup).

6 VOLTS/POS. GRD. NW INDIANA

Rocker geometry is both a wear issue and performance issue.  Poor geometry increases wear and decreases lift.



Lawrenceville, GA

Right. I was confusing ‘rocker’ geometry with ‘adjuster-ball/PR-cup’ geometry. Mostly a wear, rather than performance issue (?).

6 VOLTS/POS. GRD. NW INDIANA

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Here is how Ted and I solved the problem on the 2018 303Y for EMC.  Iron head rule, 1.6 Harland Sharp roller rocker arms, Smith Brothers push rods, etc.  Joe-JDC

JDC

They are as thick as necessary.  Required thickness will vary from one build to another.  I have made others.  Here's the easiest way I've found to make them without a machine shop.  3/4" wide strip and a lot of care a patience with a belt sander although if the required dimension is significantly different than standard metal thicknesses, i suggest a machine shop.





Lawrenceville, GA

Here's a link to Ted's article

https://www.eatonbalancing.com/2007/12/10/rocker-arm-geometry/

When I did mine, I also came across a technique that I think is called mid-lift.  I can't find the article now.  That method states that at mid lift, if you drew an imaginary line from the valve tip (or roller axis for roller tipped rocker arms) to the center of the shaft, that line should form a 90° angle with the valve centerline.  It makes sense as that would ensure that rocker tip travel across the valve tip is minimal.  As such, I set the valve at mid lift (cam lift x rocker ratio - lash) / 2 and was able to make a rough measurement of how much the stand height would have to change in order to achieve that 90° angle.  If you took very careful measurements, you can probably calculate it exactly.  That gave me a god starting point.

A checking pushrod is advised for this simply because the required pushrod length will change with a change in stand height and the rocker ratio changes as the depth of the lash adjusting screw is changed.  The checking pushrod allows you to keep the adjuster screw locked down so that the variables can be kept to a minimum.  It also helps you figure out the length of pushrod you need to order once the geometry is where you want it.



Lawrenceville, GA

Nice job on the shims, Charlie, but they look a bit thick. Have you made others?

Ted did an article on this subject some time ago.  I do not have a reference to it.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

... i wish i would learn to keep my big mouth shut ...

Either TED or JOHN should have a TECH ARTICLE written on PROPER VALVE-TRAIN GEOMETRY and how to get there.

You would start (IMO) with adj. checking push-rod(s) to find proper rocker arm/valve stem contact/sweep and go from there wouldn't you?

I have always wondered why FYB push-rod length(s) differences (between model years) was never really discussed, especially between differing rocker arm ratios.

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