RE: TAMS A-4
The weight of the motor is not the whole story though. The way a 60 absolutely eats gas, you have to carry more of it. A 100 might well be just as light with 7 or 8 minutes of fuel on board. I'm sertain that a Wren SS, Merlin 90, or Rabbit would.
Check out the comparison table in RCJI for specifics.
Don.