Upper coolant hoses Collapsed

[Skybolt]

My 6CTA's did that on my 460 the entire time that I had the boat. I replaced caps, hoses and it stayed the same. After a couple years I didn't give it any further thought, the boat ran great and never had an issues.

I would have to say you got lucky. Anyway, not trying to overstate my point. The caps and hose are probably fine, it was probably overlooked when testing from the factory or just a bad design (under spec'd hose). A nice SS spring would fix the whole thing, assuming there isn't another issue causing this.

https://www.ebay.com/itm/Lower-Radiator-Hose-Spring-/114221340211