Trap Door Inside Exaust Manifold

You definitely want the manifold heat system working. It's a common but mistaken notion that blocking it off or removing it on a non-race vehicle is beneficial. You could get around its necessity to operate the automatic choke (no, the intake will not get hot enough to open it on its own without exhaust heat) by installing the applicable electric choke kit (link is for slant-6s; they have them for V8s, too) but you still want it operational even if you have a manual choke or none at all. See this post and this one.