I am building another UCD 60 and I am putting a Magnum 120 2 stroke in it. I have heard that people have done this and I tried it on my last UCD 60. I had to re-drill the firewall to fit the larger motor mount, but the holes were so close to the sides of the firewall that I had to cut into some of the triangle stock so that the blind nut could fit. How have any of you guys done this? I am wondering if cutting into the triangle stock will weaken the firewall too much.

I was thinking that maybe I can drill teh motor mount to fit the existing firewall holes.

Another thing. i am mounting th tank on the CG. Now there will be that big hole on the firewall where the stock tank fits. What can I do to block that hole up so that fuel will not go into the fuselage.

Thanks for the replies.