Need some help. I sent back a HDS7 due to a malfunction and Lowrance replaced it with a HDS8. The transducer I have from the HDS7 fits and powers up the new unit, but the transducer that came with the HDS8 has a much larger head. My question is, if I use the old transducer will it effect the way the new unit operates. I don't want to drill more/new holes in my boat I dont have to. Thoughts???