According to the manufacturers specs the 5.8 weighs 6.0 # and the 80 weighs 4.2 #. These are bare engines. I had to add about 1/2 # to the nose of the Decathlon with the 80 up front.

My Decathlon weighs 32 # and just barely has unlimited vertical. To have sparkling vertical for a ZDZ80RV the plane needs to weigh about 24 #.

Ken