I've read of a few people here who have lengthened the fuse 4 inches and added 1 additional rib bay on both sides of the wing to accommodate a 60 size engine. I built mine stock with a tt 42 engine and am having a blast with it! In my opinion you can't beat it for the price! Just make sure you do not follow the recommendation to cut out the fuse where the landing gear sits, it creates a weak spot that you will be fixing all the time.... ask me how I know!