I have two your bikes little bothers.
an 850 and 750.... The 850 is a regular ride.
Funny thing is dad has a 1500 Intruder in the shop too, he would rather ride my 850 it handles better and is easier to ride.
I have a standard gas tank for the 850/750 I'm sure the 1100 is the same.
But it doesn't fit well in the Special frames. They are entirely different.
Not sure they ever used the Hitachi carbs on the 1100, but if they did be prepared to trash them if they give problems, parts are nearly impossible to find.
One more thing, they two lines on the petcock one is actually vacuum cut off so when you shot the bike off, it stops the gas flow.
These bikes are getting old enough the diaphrams in the petcocks are going bad it lets it leak gas into the vacuum port on the manifold.
If you develop this issue MikesXS sells a regular petcock with on/off/reserve as these should have had.