Below is my son's beaten up and many times repaired 40 trainer which now sports a 1.08 engine with the nose shortened by about 3" to help keep the CG correct. AUW increased from 5 1/2 pounds to 6 pounds which gave an unnoticeable increase in stall speed and the 14x6 prop combined with the much lower revs of the 1.08 kept the maximum speed virtually the same as with the smaller engine so aerodynamic loads in manoeuvres are also similar. In short, it's a blast to fly and wayyyyy better than with the original engine .