It doesn't seem to stress the lines nor fittings.
I changed the tank out from the stock bottom feed that had the short rubber line to a new top feed tank/sender.
The extended length of the new line and new rubber grommet allows for slight movement under the cab and holds it stable above in the cab.
Time will tell.
If you drive on modern roads you will probably be OK. If you drive on the farm back 40, for which these trucks were designed, then you would likely have trouble. Lots of flex in these 'ole gals'.
