I use an O.S. 18 tz buggy motor with the fins cut off down to the 3rd fin and it still runs cool.A mac 3.5 high nitro or low nitro pipe cut to 3" from the glow plug(Glenn's recommendations). Also I use a 6 oz. sullivan flexible tank to give you more run time. If the 18 is set rich it uses up the 4 oz. quickly. You have to change the crank out to take off the pull start (it won't fit in the tube) and use a flywheel with belt starter. Also, through bolt the motor mounts, the screws will tend to pull out with the constant pulling upward of the motor during starting. Zipp has a 38 mm x 53 mm prop that works well with some work done. Hope this helps.