Oil pump intermediate shaft breaking

Just to add to what has been said;
the Drive, and the HV pump, in my 367 came out of the DC catalog, and were new in 1999.. They now have over 100,000 miles on them. The last time I inspected them was 2005.
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My Barracuda only runs the factory gauges, so, IDK what my oil-pressure truly is, except to say that; one time,
I installed some 15W40 in the sump, and the first time I revved it up a lil, she promptly blew the oil filter off the block and pissed oil all over the header.
I fixed that by adding a second plate for stiffness, and doubled the number of holes in the plate, and installing a plate retaining fitting that had the hex on the outside and a round hole inside, which I drilled bigger. But after that, I never ran 15W40 again. and she never leaked there again either.
The point, I think, is that, the HV pump is a pretty good pump.
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To take advantage of the higher volume,
I ported the passages from pump to the main gallery, drilled all the passages in the block bigger, and supplied more oil to the top-end. I think there is an oil-mod sticky back on the opening page. I did all that except the oil-crossover, cuz I was never planning to go over 6000 rpm. That only started after I missed a few shifts and learned that the engine didn't seem to mind 7000. After that it was game on!
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The more oil to the top end was for lubing the aluminum rockers on the steel shafts/no bushings, and for cooling the springs, which are robust enough to run 7200 or more, without losing control.