My first suggestion would be to find a rebuildable W1 because this is the carburetor that was made to work with your truck.
Here is a link to information (
https://www.thecarburetorshop.com/CarterChevroletW1.htm)
You are asking information, from a Chevrolet truck forum, about an IHC carburetor.
I would find an IHC forum and ask the specific questions.
Try this. I found the attached picture and it also shows the website below.
Jon's website (
https://www.thecarburetorshop.com/TruckkitsI.htm#TkitIHC) lists the YF735s as used on a 220 CI engine which is slightly larger that your 216.
I don't know for certain if this carburetor will work well on your 216 engine. If I had no other option, I would try it out.
Considerations:
Throttle linkage fit.
Throttle base fit to manifold.
Vacuum advance for distributor.
Air cleaner fit.
