I replaced these hoses on my 1970 164.

Were I you I'd also replace the valve. It has a "keep the
temperature constant" sort of feature but I only ever used
it in the open or closed position. There is a totally self
contained valve on 80's VWs that could probably do the same
thing with fewer moving parts. The constant temperature
valve thingy on my 164 was broken and always open. Living
in a desert, this was not a good feature.

I don't recall these hoses as being super hard to replace.
I actually used generic wire reenforced hose instead of a
volvo specific part. I had taken some of the heater box
and dashboard guts out and did much of the manipulation of
these hoses from inside the car, not from above the motor
in the engine bay. I also used something (oil? soap? I
don't remember) to help sliding the hoses onto the different
things the hoses were suppose to attach to. It was tight
but I was able to do it without too much fighting, but I
seem to remember that I did have to do it blind.

Hmm, I'm rambling.
chris