I did the cucv radiator swap on my K5. It fit fine but the radiator hose nipples are different sizes (for a big block). I used the fan shroud too.
For the top nipple, it was too big so I had a rad shop braze on a new one the right size.
On the lower I used the cucv diesel hose. The hose was bigger than the water pump so I cut a piece off of the 454 hose and used it as a bushing to make the cucv hose fit. Works good with no leaks.
Edit: I didn't change the lower hose nipple because the shop was giving a bunch of bs about wanting to replace the radiator. I took what they had done and went with it.

Surely you're not going to be something that nice. 
Having all that stuff powder coated really makes it look good!Surely you're not going to be something that nice.
![]()

