Anyone here ever done a TPI Conversion on a C3? I am currently doing a frame up build on a 69 coupe that originally had a BBC 4 speed,  Engine and tranny had been sold before I bought the car.  Frame and Birdcage was cancered out with rust.  So I have a alot of room to work with, and build it the way I want.  I have salvaged the interior, t-tops, front end,doors, wiring harnesses and suspension.  Bought a super clean body, and replaced the frame.  Both are Automatic ready, and am slowly sarting to go back together with it.  Upgrades in the suspension from VBandP, where I have been able to afford it.  I have alot of Under the hood BBC components that I am about to start getting rid of soon, to help finance the rest of the story.  For those of you that might be interested. 

TPI set-up will require a sizable hoodscoop to fit, and of course the O/D trans will need some mods. Both will work fine...just need to be ready for some planning ahead. The TPI is gonna need a computer system and associated wiring, along with all of the sensors(MAP, TPS, O2,etc.), and an electric fuel pump designed for that system.
If you're afraid of nightmares, I'd vote to go back old school with carb...but that's just me.

Another alternative is the 92-96 LT1.  It was much lower profile.  And the 200R4 transmission was the same length as your TH400.  It sounds like a fun project.

Larry

Unfortunately I am not afraid of nightmare situations.  I actually kinda thrive on them.  I guess its the challenge of it all, and finding the solutions along the way.  I plan on getting the complete computer system along with what ever I buy.  I bit the coupe off knowing I was in for a serious "project" and not just a car that I was gonna just get in and drive from the start.  THAT is the fun of it all.  I do have the Original Big Block hood, so that is a plus.  Still leaning towards just ordering a nice crate motor fromthe dealer and being done with it, but I do want the OD tranny.  Never thought of the 2004r though.  Thanks for the suggestions.  One thing about it.  Going back carburated would sure make it easy, And horsepower is all about the basics, rather than programming.  Decisions, Decisions.........

The best set up is one from a corvette, get the weather pack computer for the corvette and it will install in your engine compartment insted of cutting a hole in your firewall. I had a system for my 72 and was going to do that also but decided to stay old school. You will need to modiify your fuel tank sending unit with a return line not to hard to do. If you need injectors look at the junk yards, look for a GM car with a Quad 4 engine, they have 22-23lb injectors much cheaper because nobody wants those engines so parts are much lower.

FAST 9Fuel Air Spark Technology) recently released a throttle body injection system that is truly plug and play.  One of the car magazines bolted it onto an engine and made a dozen dyno pulls.  It "learned" over several of them, and made more power than a carb.  They then transfered it to a modified big block, and it learned all over again.  It is called EZ-EFI.

Larry

Do you have a list of parts you are willing to give up. I am just starting a big block conversion on a 1980 Corvette. I am also going from automatic to manual transmission. Let me know.

Not sure who you are addressing for the part's? I gave away my system.

I will be posting the BB parts that I am doing away with, as well as manual tranny extras, (clutch pedal assembly, bell housing, shifter, etc...) as soon as i get them all together,cleaned up, and priced out.

I put a TPI under the stock hood of a 78 with no problems. use a fuel sending unit from an 82 in the fuel tank just update the pump. it is plug and play pretty much. I would use the speed density system over the mass airflow for simplicity but either one is easy to do. Do your research first and gather parts. you dont need a donor car. it just makes it easy but costs more. the parts come easy enough and cheap if your patient. I have scematics for the computer. Use the weather pack as suggested. The large distributer is desirable but is a pain to get in and out of car. if you tilt the motor you can get it in and change any components when needed without removing the whole distributor. If you run into any snags let me know and I'll tell you how I overcame it. Good luck. The car is super reliable with this system.