I have a 89 firebird with a 305 TBI and a th700R4 trans. Can i convert my engine from TBI to a carb, and if so, i know i would need to get a new intake, a carb, and a new ignition system, but would i need to do something to my trans such as, does the comp shift it now, and if so how could i get this problem covered. The reason is because i bought this car for $800 and the engine and body are really good,and strong but the guy who had it before me kinda unplugged like almost all the harnesses under the hood and some were even burned from the heat. This is the reason im thinking the check engine light is on and I just want to get rid of the computer and all that junk! Please help me! thank-you

Damian  

Blu, yes you can install a carb, Edelbrock make a Performer intake that will bolt to your iron head 305 and accepts all 4bbl carbs-Hollet, Edelbrock/Carter, Q-jet. You will need an HEI distributor from any non-computer controlled small block Chevy, 70's to early 80's will do fine. You may want to install a timing curve kit as some of these HEI's had a very lazy curve. Your trans will require a correct throttle arm adapter to run the TV cable (check out Bowtie Overdrives.com for the proper adjustment procedure and installation). Your trans only needs the computer to run the speedo and lockup, so you should be ok.
On the other hand it will probably be easier and more effective to source a replacement harness from a wrecking yard and fix your TBI, the car will likely be far more driveable and get better mileage with the TBI, not to mention any legallity issues if you require an emissions test. The TBI system is a really fine working and reliable system, if bone heads like the previous owner would leave them alone. I would fix it, rather than swap it.
Steve  

I would also fix the TBI. It looks like a daunting task now, but swapping back to a carb is even more of a pain! Get a replacement harness, it's not as hard as you think to replace. If you have the opportunity to pull one from a junk yard just tag and mark everything you unplug.  

as far as building it up and being able to work on it better, you really suggest keeping the TBI? I was going to fix a few things first like get a master rebuild kit for the trans and then check out how the rear end is holding up. The thing is I HATE the computer, and I know someone who could help me get the timing right with the gun. I don't know, maybe to me it just seems like it would be easier to work with a carb rather then a comp showing me the check engine light! But, is it really thast much better to keep the TBI though?

Damian  

I would say so. I don't think that car would ever be right if you tried to get rid of the computer. You're gonna open a whole new can of worms!
A friend of mine has a '89 Formula 305 EFI 5spd. All we have done to it is hang a set of headers and good exhaust, set the timing at 8 deg BTDC and consistently run 89-90 octane gas. That old bird impresses more people than you will ever believe.    

Here's a thought for you, why not keep the TBI, bolt on a set of aftermarket heads, Edelbrock TBI intake, one of the EFI cams from Comp, Crane or whoever and some good headers and exhaust. Several companies make headers with the crossover pipe and high flow cat and cat-back exhaust systems. The thing to remember is that most times when guys try to do away with the computer, they end up causing more trouble. The fact that somebody already damaged the system is proof of what happens when people with no idea start messing with things. GM's TBI is one of the most reliable and fool proof systems out there, just look at how many pre-Vortec GM trucks and vans (including 4.3 Astro/Safaris) are on the road. The main thing to do is replace the harness, then take it to the dealer to check codes and diagnose the system. Don't let some shadetree mechanic try to tell you any different, too many parts get changed because "buddy" says that what was wrong with his car, or let's try this first. Your bird will be better off with a proper functioning TBI than a cobbled up carb setup.
Steve  

On that note, the GM Vortec heads are a pretty good upgrade. They are very plentiful in almost any good junk yard with trucks, and should be pretty cheap.
But before you get carried away with big time bolt ons, you might consider a basic rebuild with that many miles on the clock. But first things first, get that wire harness mess straightened out.