Hello, I am James! Welcome to Horizon Hobby, how can I assist you with finding the right item to suit your needs?
Will a Desert aircraft engine work on this engine mount?
Sorry I am not sure which engine mount you are looking at? But all the DA engines use 4 standoffs that mount to ears on the motor and then directly to the firewall.
So will a da 35 work on this plane without firewall modifications?
Let me take a look at the firewall real quick.
There are already 4 pre-drilled holes in the firewall, so it would possibly need to have those plugged and redrilled for the DA35.
Well I want to be sure so what can I do
Unfortunately with out being able to actually measure the pre-drilled holes there isn't much of a way to know for sure. It would be something rather simple to work around. You could also possible contact the Horizon Hobby Product Support Team and they might be able to measure the mounting holes already drilled.