As a general rule all the engines are quite good at holding a tune once they are tuned correctly...... Usually when a engine chronically needs to be re-tuned its a sign of a underlying mechanical issue, as a healthy engine should rarely need to be needled......Its not uncommon for me to run several gallons of fuel and not touch my needles once....And this goes for any of the engines I have listed.....Most peoples issue is they don't let the engine properly warm up and try to tune on the starter box, which ends up throwing everything off once they get onto the track..............