What is it about the 40LA you don't like? For a trainer, it is a most ideal engine. What prop are you using. Mine does very well on an ASP 11X5 and 15% cool power. Mine is on a WM Mach I, a fairly large trainer, and this engine hauls it around perfectly as a trainer, teaches good flying habits and the plane is capable of basic aerobatics, including sustained inverted, inside and outside loops and even knife edge.

The OS 46AX is a terrific engine, but for a trainer? C'mon.....