Any engine can be cowled, you just have to be sure it has adequate airflow into and out of the cowl...

A remote needle valve is one that is not mounted directly on the carb, but usually is attached to the engine's backplate via a bracket. An extension (usually a piece of 2mm wire ) is used to make the needle adjustable from outside of the cowl.

Your thread title says .46 but the post says .40, which size are ya looking for?

A good .46 is the Thunder Tiger .46 pro, which can be had for about 80 bucks.