So it's been a while. Sorry for not being able to contribute much of anything but I did want to share something that a friend made for me. It's nothing fancy dancy, just an adaptor plate that lets you adjust the position of the TBI over a Holley square bore carb intake. It has 2" bores but is only 1/2" thick. With a stock small bore TB you won't have any problems with the blades hitting the intake manifold walls... not the case with the big bore TB. Some minor grinding/dremeling/filing is all that's needed.
Oh, and after playing with my options I might no longer be TBI. LS1's come bolted to T56's and I can't find a Lt1 T56 for a decent price... not what I wanted... or was it!
Good luck to those keeping the TBI. I held out for as long as I could but with NJ inspections and gas prices the way they are I just can't afford to play those odds.
This one is NOT for sale but if there is enough demand I can get a batch made up. Let me know what you would pay for a bare part, no hardware/gaskets.

 

I understand the feeling and know where you are coming from.

I recently swapped my 1994 G10 to TPI run by a late model Vortec 305 PCM. Sequentially injected TPI. I like the fuel mileage that the cammed 305 is getting with the sequential PFI as well as the instant throttle response.

I think that my 1983 is staying TBI though.

 

Im trying to put together a gen I fuel injected roller cam 302 and noticed your comment here as well as a response seeming to indicate tbi gets poor mileage. Was wondering if you could comment on the merits of tbi tpi and vortec as possible fuel systems for my 302 in a 2900 lb car mileage wise. I drive a Marquis 50 miles to work every day and the ford tbi 302 factory setup in a 4500 lb car gets 18-20mpg with 200k on it. Also impact of a turbo mileage wise. Thanks for any help