Thanks for the replys. I basically took the original box, lopped off the angles and reset the firewall so that there were no angles. Bad move I know. The box did have tabs, but the tabs are no more. I set the firewall in with epoxy and reenforced with some small screws at even points around. I then fiberglassed over for added reenforcement. Overkill I guess but its pretty firm. The ARF itself is beautiful. Having the smaller versions and knowing the beauty of these when complete, I was frustrated when I saw how screwed the engine sits. With the prop and spinner on it and set in at the original angles, it was almost like it was pointing down. I don't know, maybe if someone else on here has ever built one of these I'll get more suggestions. Ultimately, I'll do as you said and prob build another box around this one. I'm assuming with these bigger planes and more torque, rudder comes into play alot more both on taxi and flight.