Would there be any harm in opening up the bottom of the adjuster hole on the rocker rm to allow a cup adjuster to fully seat on the rocker? I will be push rod oiling so I don’t really need the adjuster down where it can be hit with the oil from the back side of the rocker.

Run it like it is

Why do you need/want to do this?

Are you thinking of the impact this has on the rocker arm ratio? Or is this dictated by the length of pushrods you currently have?

I'd plug those holes. Get some appropriate sized aluminum rod. Cut 16 short pieces. Give 'em a tap with a hammer so they're a tight fit in the holes then tap 'em into place.

What do the instructions say on those rockers as far as where the adjuster cup needs to be in relation to the rocker arm body ?
Follow and use those instructions to the T

On top of that, consider removal of any metal will weaken that area, proportional to how much you remove. If you are anywhere near stressing that rocker arm to its design limits, you risk failure.

These are Crane Gold rockers and I bought the PRW adjusters to pick up some lift, as I was losing over .020 with the Crane ball adjusters. Because the oil hole points so low you have to run 3-4 threads showing on an already tall adjuster, so the kick-out is pretty extreme. It looks like if I just relieve a small portion where the flat meets the round I could pick up .030-.040 and adjuster would sit flat on rocker and possibly distribute the load a little better. I do not have pushrods yet but while shopping I did noticed there is better pricing, more availability and more options (i.e. tapered) to certain sizes, so having a little more room to adjust and getting the pushrod as long and strong as possible is a goal. You can find some pretty nice NASCAR leftovers on the cheap. I am running a mild flat tappet so I am only 150/350 on spring pressure so I don’t feel like I am pushing anything stress wise well I do spin it 7,000.

If you are losing that much lift you have the adjuster too far out.

If you read the Chrysler engine book they tell you EXACTLY a how far out the adjuster should be with the oil feed hole in that location.

It is 9/32 inch. There is a plus minus and I *think* it’s plus zero, minus .020 but it could be the other way around.

There should be no threads to maybe one thread showing. That’s it. Screw an adjuster in there and set it at 9/32 and see what it looks like. If you had 3 or 4 threads showing you’re doing it wrong.

I am going to go with a picture is worth a thousand words. The angle of the oil hole creates the need for the lower adjuster position in order to oil the cup. When I measure the distance from the bottom of the rocker to the ball, I get about .425 (the picture is not dead above so it looks like there is more). When I measure the cup adjuster, I get .185 and when you subtract the distance to the actual bottom of the cup you can subtract another .115, so net is .070. This reduces the pivot point by .355.

OK, so rocker arm ratio it is!

Well, the closer the pushrod pivot is to the continuation of the rocker arm's nose centerline (as it cuts through the center of the rocker body and exits through the oppossing end), the higher the rocker arm ratio you end up with. The rationalle there being the distance from the rocker arm pivot center is shorter and subsequently that produces a more direct and therefore larger movement at the rocker arm nose. The further away from that ideal straight line you get, the longer the distance from that pivot point to the rocker arm pivot itself, and therefore the lower the rocker arm ratio.

I played around with this on my 1.6 design ratio W2 Harland Sharp rocker arm setup for a different reason (explained below). Specifically I measured the difference between setting up the adjuster to show just 1 thread below rocker arm body vs 3 threads, so a difference of just 0.100" on a 20-TPI adjuster.

The resulting ratio average over the full lift of the lobe (so comparing the actual valve movement vs lobe lift) netted me the following results:

1) 1 thread => avg ratio = 1.550
- the geometry uncorrected ratio was actually 1.593

2) 3 threads => avg ratio = 1.526
- the geometry uncorrected ratio was actually 1.619

...the result was NOT significant enough to lose sleep over, however it spelled out the lift difference I was looking for, that being an avg lift loss of about 0.011" on #1 and 0.019" on #2.

Now the reason for this: I ordered the B3 geometry correction kit and knew ahead of time that the resulting valve lift would be smaller due to the correction of the rocker arm movement itself (all in the name of improved valvetrain stability).

So from my perspective: is the benefit worth the potential machinig cost (to clearance the rocker arm) and the potential weakening of the rocker arm body itself?

That adjuster is too far out. Set it at .287 down. That’s where it goes, per Chrysler.

I’m not going to type all of out but you are trying to re-engineer something that works.

The LAST a thing you want is to try and get the oil to squirt into the cup. It wasn’t designed that way. It needs to hit the adjuster above the ball and then run into the cup. And that’s per Chrysler.

Edit: I forgot to mention that it is highly unlikely that the hole in the shaft even lines up with the hole in the rocker. That’s on Chrysler.

Mad, I’m not following, if I set it to .287 the oil flow will hit the pushrod below the cup and not on the adjuster at all and if it needs to hit the adjuster above the ball then it will have to down more than it is now.

Here is a picture where I have a witness mark of where the adjuster hits the rocker arm. I was thinking I could cut it back .020-.030 and maybe have it seated. It would basically be the same as the relief for the spring retainer on the other side.

For whats its worth. I have done what your asking and never broke a rocker. Even with roller cam springs.

Like has been mentioned, you can swap over to a cup adjuster for ball/ball pushrods and yes, I'd only do it with pushrod oiling. yes i have found that you will increase the rocker ratio by pushing the adjuster up into the rocker body on every style of mopar rockers that I have played with. Also, LIKE IT HAS BEEN SUGGESTED, I'd plug the rocker oiling hole as suggested.

What is the primary reason to block the oil hole? Is it just robbing too much oil from other places? I'm not opposed but wanted to understand the reason to do it.

Is it better to force fit something in or thread something in the end?

for what its worth, I've run them flush to out a couple of threads with no oil mods and never smoked a push rod.

I decided to give it a shot. I grabbed another rocker and it was different than the one pictured above as it measured .230 (rocker to edge of adjuster) as it had no relief at all whereas the first one had a little. About 30 seconds with dremel and I was able to pick up .030 in depth and it is consistent with the first one pictured above, so it looks like i need to check them all so I can have some consistency.

how can one tell the crane adjusters from the prw ones ?
i have a set of crane gold rockers, but i don't know what adjusters are in them.
TIA for the knowledge i don't possess.

Manton adjusters are WAY better than the Smith Bros. I've used, the Smith Bros.sucked

Not sure how to tell the adjusters apart. I bought a set of Smith Bros to replace the adjusters on my 1.7 CAT rockers, and to lay them next to one another not sure you can tell the difference.