The answers to your questions are in the
Shop Manual. It is quite possible that the feed tube is leaking. Not easy to replace or work around.
Unless you really want to keep a 216 in the truck, a full-pressure 235 or 261 would be a great engine. The 1953-54 engines are are an easy replacement, and the 55-62s are not much of a problem to install.
Hoyt
