Grumpy old man gave a link to a marine engine supply here in this post:
https://67-72chevytrucks.com/vboard/...05#post8858005
There is also discussion on that thread and some other threads about using heater hoses but I'm not sure I would take that approach because it would not be fuel and oil resistant material (EPDM rubber that Gates part #28475 is made of is not fuel and oil resistant).