Just a couple thoughts:
As long as smog inspection isn't a consideration, you will need the motor mounts for a V8, as well as a V8-spec tranny to replace the 4 cyl. unit you now have- one from a 3'rd. gen F-body w/the torque are unless you're going to replace the rear end- which should be considered because the 7.5" diff is weak-kneed.
The radiator and shroud from a V8 car is needed. I'd also plan on an auxiliary tranny cooler while I was at it.
You may be able to use the TBI fuel pump, if you regulate the pressure down from the ~15 psi it now has to around 6 psi or so, for a carb.
AFA the sensors, etc, you'll not be able to use the PCM so about all that would be reused from the TPI set-up would be the gages for oil, temp, and charging system. The rest will be unused.
The front springs (at least) will need to be replaced most likely. If it was a V6, you might have gotten away w/o replacing them, but I'm fairly sure the 4 cyl. springs/struts will be wrong.