It’s actually not that uncommon with a hyd cam and either the Comp or PRW rockers for the pushrods to fall out.
The situations I’m familiar with happen on start-up, not while it’s running or being revved.
The root cause is a lifter bleeding down after the motor is shut off and the plunger is at the bottom of the lifter, combined with pushrod cups in the rockers that aren’t very deep.
After the motor is shut off the lifter bleeds down on a valve that is on the closing side of the cam and the plunger gets bottomed, and then you have the valve resting on the seat after the lifter is bled down.
When the motor is cranked over on the restart and that lifter goes back down in the bore, but the rocker isn’t trying to follow it because the valve is already closed, and the pushrod falls out.
I know of this happening with both hyd flat and roller cams.
Never with any solid lifter cam.
It seems to happen more when the lifters have very light preload in them.
I haven’t tried it, but I suspect running more preload would help.
We had a 440 here with PRW rockers that this happened to numerous times.
Different pushrods each time.
This was my first experience with it.
We switched to the Mancini HS rockers and cup style pushrods.
The cup in the pushrods was noticeably deeper than the cup in the PRW rockers, so I figured it would be harder for the pushrods to fall out.
We also went with a little more preload.
Never bothered again.
With the PRW rockers, a couple of times the pushrod didn’t fall all the way out, it just slipped out of the cup and the pushrod was wedged into the corner between the cup and the body.
After we experienced it here, I talked with several others who had similar stories. Most of them solved it with solid lifters.
Like I said, this is referring to instances when the pushrod falls out during start up........not any other situation.
As for the Stealth springs giving up...... I have no idea how well they hold up, but that’s a pretty low cost item to replace for some piece of mind.
As a side note.....The XE series of cams just aren’t that well suited towards higher rpm use.
At 5700 there is already likely some unhappiness, and the pushrods going through the rockers is the tell tale that things are not running super smooth.
Running a hyd cam in a “race car” is false economy imo.
You get less performance, and when used with stock replacement type parts the reliability isn’t always great.
Run a solid cam along with some sort of aftermarket rockers right from the start.
More power, more reliability.
Or, if it has to be a hyd, use something with smoother lobes.
