Jeff et. al.,
I am contemplating the same for my rear heater as I don't need two in SE
Texas. I would not plug feed and return, I would insert a joint of
copper pipe to complete the loop, otherwise you will be asking to have
an air bubble in both the plugged feed and plugged return lines. Those
bubbles (trapped air) would do no good things but have the potential to
give problems.
Mark B. Magee
87GL
82 Diesel Westy
Kemah TX