carb to TPI
 

'85-'86 TPI base will bolt to your heads (assuming you have '73 heads on the 350). '87-'92 will if you modify the center two mount bolt holes on each side of the base to be the same angle as the rest.

Power will not increase, assuming you have the carb set up half-way decent now. Throttle response and economy will most likely increase. What you have to modify depends highly upon what how complete a TPI setup you get.

Re: carb to TPI
 

Let's assume the TPI setup that I get is as complete as possible what sensors would I need and what would I have to modify? Also on a scale of 1-10 how hard do you think it would be to hook up the computer and wire everything?

Re: carb to TPI
 

I'd also add reliability and less frequent maintenance to that list of advantages of TPI.
One thing I've wondered is where would you put the knock sensor on a motor that didnt originally come with one?
O2 sensor is easy, an exhaust shop could weld a bung in for one in a few mins.
You'd have to get a high pressure (electric) fuel pump as well.
When I swapped in a TPI motor (complete) into my 76 vette, I sent out the TPI harness to a company in TX that did the modifications for me. Worked great.
You'd also have to swap out the air box/snorkel, but that shouldnt be a problem.

Re: carb to TPI
 

The block should still have a "drain hole" on both sides of the engine in the bottom center at the oil pan rail. Remove one of the drain plugs (stock is the passenger side) and install the knock sensor.

See the tech article on this site about swapping from TBI to TPI, it will give you an idea of where to start. If you dont have any electronics or mechanical experience, this will be a difficult job.