My original Super Tigre NVA Fox 35 ran great. If drilling the case to get it in was needed, and it restricted the venturi a bit, I didn't mind. Fuel draw, economy were great. I miss that engine. Also had a good fitting chip muffler. Probably a 50th or 60th Anniv. Thought I'd never fly Fox 35 again. Now I am rigging advanced trainers setup for Fox.
Back to the NVA, I'd say an original Super Tigre or an RSM would be fine, even an Enya if that's your style.
Peter