Exploding water pumps? Difference in early 273 water pumps vs later 1970s 318 pumps

AJ/FormS said
I wonder what stewpot of parts I lucked into when I just screwed my stuff together.......

But I see you are running a tiny fan pulley, looks to be extremely small. My guess is that the ratio is something like 8 to 5=60 effing percent overdrive!
that means your pump is spinning 60% faster than the crank. And that means by 5000 crank rpm, the pump would be doing over 8000. It wouldn't take much of an imbalance to shake it apart.
I can't imagine why you would run it like that.

Are you having over-heat issues? Those are usually easy to solve.

yes it’s the smaller diameter pulley, original to my car which came with factory 1967 AC, I might swap it out for the larger one think I have one in my shed I’ve had two bearings go out in my water pumps that also might be a reason why the engine isn’t stock and it revs up to 5200 rpms before I shift, this all happened when I was doing a burn out so ya this is good to know