ORIGINAL: energyman
The Evo 40 displacement is 0.402 cu in. based on the specified bore and stroke. Did the math.
I measured the Evo 40 in my shop and the displacement is 0.395 cu in. Bore 0.851'', Stroke 0.694''. Measured it several times.
Which one do you have?
They had the 40NT. It was a .40
The 40NX is not what you measured unless Horizon can't measure their engines and the Evolution 40NX is what is available for purchase now. The specs are in the manual here [link]http://www.horizonhobby.com/pdf/EVOE0401-Manual.pdf[/link] and on the products page here [link]http://www.horizonhobby.com/products/40nx-rc-glow-engine-with-muffler-EVOE0401[/link]
Pardon my short answer. I shouldn't respond while I'm working on a problem.