Will you be using the 6v or the 12v starter? You should use the flywheel and starter from a year that used the voltage you are using in your truck (6v, if original).

You may need to change to a short-shaft water pump (someone who knows about the fit in 1941 will answer this one).

You should use a clutch-housing that matches your truck's year. And, a clutch assembly that matches your year/clutch-housing/transmission (I assume this is possible - someone with correct and/or explain).