ORIGINAL: qwertypemdas

I have an LT-40 trainer with an evolution 40NT engine. 8.5lb plane with a wimpy .39 engine. Full throttle barely lifts off ground. I'm looking into a tuned pipe to get a little more performance out of my plane. What is the CHEAPEST header and tuned pipe the will work for the evo 40? I built a mousse can muffler but my dad (he doesn't do rc stuff) won't let me put it on my engine. [:@] I just need the cheapest dirt (maybe used?) tuned pipe and header for the evo 40. I REALLY need more power so is there a cheap pipe that works really good? hmmm.