Engine valvetrain assistance

Long winded but bare with me.
My son was driving my ex's 67 mustang when the engine started making some racket. I told her I would diagnose the problem, being as my son was driving it at the time, and go from there. The issue was determined to be a broken valve spring (Dual valve spring to be exact). So I took it to my engine guy and there were other issues going on; some worn valves, worn rocker studs, etc. So he replaced a few valves, ALL the rocker studs and all new springs.
Here's where the question comes in. The ex opted to replace the stock rocker arms with roller tipped rocker arms. The rocker arms came with what I'll call retaining nuts with an allen set screw lock. I went to install the rocker arms and nuts, the nuts would bottom out before they became tight. So I had my engine come out and he said "there's your problem" He had the "right parts" back at his shop and would come back in a couple days and help me button everything up. Then.......... he decides to have himself a massive heart attack. Short story long, he's been a coma since his heart attack, so needless to say, he's not much help.
I did some research and found that apparently, there are not longer retaining nuts available. WTF......
So then I got to thinking "IF" he was planning on the ex using a thicker billet style roller rocker arm, then the retaining nuts should fit, but essentially, the rocker arms I have look like a stock rocker with a roller tip. So I got to thinking what if I were to swap out the existing rocker studs with a shorter "stock height" stud, then I should be able to use the parts I currently have.
So am I correct in my assumptions?

Bear in mind, I know just enough to be dangerous. If it was my car, I'd just figure it out and run it and deal with the consequences. But as it's not my car, it's the consequences I'd prefer to do without !!!

Engine is a mild built 302 with a decent cam and 4 speed.

 

Can't really help you with all that however I did notice a couple of things wrong with the story:

 

It sounds like you have what's called a positive stop stud which creates the bottoming out issue you're seeing here when trying to use those adjustable nuts.

You didnt say what year cylinder heads but most all factory stuff is non adjustable and needs the conversion studs if going to an adjustable valvetrain. What year heads?

 

Ha..... that's actually pretty funny. Not true..... but funny

 

Here's a couple picS of the rockers

 

Couple pics of the rocker nuts.

 

Not certain but I believe they are early 70'S vintage heads

 

The push rods look too short to me.

 

Just looked. The new Comp Cams pushrods had no part # or SPU on the pkg.
My buddy is a Ford specialist so my confidence is high that they are the right length.
But again I know just enough to be ignorant

 

Well you definitely do not have positive stop studs, someone machined them for screw in studs and those are "Poly Lock" type rocker arm adjusting nuts. It is possible that one or more hydraulic lifters have collapsed (gone bad) or push rod length needs to be checked, as installation of "roller tips" may have changed the geometry.
Also, how did you perform the valve lash adjustment?

 

Poly locks..... yep sounds correct. Was thinking that's what they were called, but the word poly makes me think of plastic

We didn't start adjusting the valve lash as it appeared the studs were too long or poly locks too short.

Here's a pic with a poly lock hand tightened on #6 cylinder. To me, it seems the set screw should be able to thread in more or am I wrong ?

 

I've never heard of using poly-locks on roller-tip rockers (but that doesn't prove anything; there's a lot of things I've never heard of). Roller-tip rocker arms are basically the same as standard rocker arms (but with a roller tip), so common sense would tell me that they would use a standard jam-nut and pivot ball like s stock rocker. At least that's what I've been running for years. Oh, and roller-tip rockers are pretty much a waste of money. The only reason I have them is because I got 'em for free. Unless you're upgrading to a full roller rocker arm, I'd just stick with a stock rocker.

 

I wasn't part of the part selection. That was between the ex and my engine guy.
As I recall, there were a few worn stock rockers so an upgrade was the solution

 

Hydraulic lfter/cam or solid lifter /cam in this engine???
From the pics I would say you have one of the above problems here:
1) Push rods too short
2) worn cam lobes (Better check all the rockers to see if they all look like your pics)
3) collapsed/worn (Excessivly) lifters
The set up now puts the roller tip waayy out over the valve tip. Roller tip should be slightly past center over the valve tip with rockers properly adjusted.
Hence the push rods too short theory. Someone didnt do their homework or, you have worn out parts as mentioned above.

 

I do know it's hydraulic cam/lifters. Is it possible the lifters have bleed down since sitting for 6 months?

You brought up some good points. With the wear on the valve train parts, maybe I need to dig deeper.

So.... before I start heading down the wrong rabbit hole, what is the proper length pushrod?