this the NGH GT17 gasser just installed on my GP Super Skybolt. Replacing an OS 91 4s, the plane does have some flights behind it. The GT17 mounted inverted instead of sideways using the same GP 60-120 adjustable mount. Fits well, and a lot neater, engine length is just right (5.8") for the cowl. These pics from break-in, note that I also switched the gear for a bit more prop clearance. The OS was swinging a 14x7 APC, the 14x8 the recommended break-in prop but the NGH looks like it'll handle a 15x7/8 or 16x6 no problem. Haven't flown it quite yet, but expect the plane to be transformed with the 15 or 16" props.