Break In Disaster????????
Kinda makes you wonder if the tubes have been crushed out-of-round....
If so much out-of-round as to leak, then I suspect you would not be able to slide the rockers over that end.
OP, the gauge suggestion is because it is easy and non-invasive, and while the other gauges' quality may not be any better, the one you have just may be well out of whack. You can't guess at it being accurate or not; you have to compare to something else, or directly measure it.
The leaks can be anywhere if the pressure is too high inside the rocker shaft. If you have not done all of the below:
- I would take of the rockers shafts and make sure they are clean, use some 400 grit wet-or-dry and polish the shafts just a bit; look inside the rocers to make sure they are not varnished up and too tight. The point is to make sure the flow OUT of the shafts is what it should be; if anything is blocked up badly, then the pressure may rise excessively inside the shaft.
- Then, take the shafts' end plugs out, (get new ones at NAPA) clean the insides of the shafts then make sure the oiling holes to each rocker are clear, check shaft diameters everywhere, and check those bolt holes in the shafts for inside diameter. Lots to check there and that is non-invasive and easy to do to be sure that is all on spec and flowing right.