I recently moved into an 80 year old house. It also has 3 wire
electric range cord and plug. The previous homeowner left the electric
range when we bought it. It was rather old so we went to Scratch and
Dent store and picked up a new radiant range with only minor scratches
on the oven handle.

Not having a new strain relief connector for the cord I used the old
one from the original range. When I installed it I was not happy with
it. If I had left it the way it was, if I were to move the range in
any way the cord would cut into the range. So I had an electrian come
over and replace the strain relief connector while I had him move and
add some extra outlets in a bedroom.