throttle valve cable geometry

Thanks for the explanation and pics... Now it all makes sense! I pulled the intake tube off my dart to confirm your thought that the fast adapter doesn't have a groove or slot for the IAC.... So you could only bolt up a 3 bolt TB if you modify the TB.
I pulled the 3 bolt off my 5.3 and took a pic, it looks like you could easily use a dremel to open that IAC port down into the main intake without getting too close to the butterfly. The FAST one on my dart the hole doesn't seem to be bigger than 3/8...