I have an access panel in the firewall of my truck. It's hidden behind the heater on the inside, and behind the engine (naturally) outside. That made it very easy to access the top connection. However, if I didn't have that, I *think* that I would have removed the valve cover and tried to loosen the hose with a crowsfoot wrench on an extension. Maybe someone else has tried this and can comment on if it would actually work.
Also, see Don's idea above. That sounds like it would work, but it's more work. And maybe the fan should also be removed before doing that?
1968 M-715 w/1100R16s on Stockton wheels, H3 headlights, 2bbl upgrade...