Dear Gray;
A l943 Chev. 1 ton truck will have a 216" engine unless someone has changed it. The difference can be seen by seen by looking at the side cover on the passenger side. A 216" will have one that attaches to the head, others do not.
In the left bourder of the web page will have a Casting #'s listing. This will "dial it in" for ya.
Good luck & welcome to the club, John M......
