I already got a 766 gas, and a Thunder Tiger 716 gasser - both UAV configuration.
My 766 has a VX310 stroker in it. It flies for 45 minutes on 1,050cc of fuel. The TT 716 has 660cc fuel and it will fly for 33 minutes. The Thunder Tiger has a stock G290RC with a TRM Power Pipe on it.
Both are equipped with Pixhawk 2.1 autopilots. I fly commercial survey work with them. Needless to say electric power just don't work for my application.
So I'll have to roll my own for the E5. I can design some frame sides and get them CNC cut for a gas conversion. If I made my own frame sides most of the parts from a Thunder Tiger Raptor gas conversion kit would convert the E5 to piston power.