I was wondering if anyone knows what all is involved in a carb to TBI swap? I'm thinking about buying my friends 305 for my 81 Firebird, but I don't want to keep it carbed. I want a good, cheap fuel injection that will make decent power. Hence, the TBI Swap. I know that I could also do a TPI swap, but the kits are pretty expensive, and I'm not looking for anything special, just something to get me to school and back everyday and also some around the town BS but not bust my wallet on gas $$. So I was going to have the 305 heads ported and polished and stick in a stock LT1 Cam, some 22# injectors, and a chip burnt for it and go from there. What all is needed for the carb to TBI swap? Thanks!

 

easiest way to go about things starts with a trip to teh junkyard. look for a car or truck with tbi. the useful bits are the intake, tb (w/injectors, tps), ecm(7747 ecm is the prefered unit), and as many of teh engine sensors as you can easily get to. another thing you shoudl try to grab is a portion of exhaust off any car that has an O2 bung in it(cut it out, pilot hole your exhaust, weld in)
you shoudl get a new O2 sensor from your local parts store, they are only $20.
you can either take the time to remove teh engine harness in the junk yard, you can order a replacement harness from gm, or you can get an aftermarket harness.
try not to grab an ecm from any car that has a VATS key. it will require an aftermarket chip just to get the thing started, adn that is a PITA + money you don't need to waste.
to mount teh tbi you can make an adaptor plate out of 1/8 steel very easily or you can get the tbi intake from the yard and alter the center 2 bolt hoels on each side as needed to bolt it down.

later
tim

 

Carb to TPI

 

Thanks for the info! I guess I'll be off the junk yard soon!

 

All v8 TBI applications had 2 injectors....

- Justin

 

If you want decent power with decent gas milage and no hassle, get a 350 tbi motor. If you do a cam on the 305 you'll need to start burning chips to get your milage back. Stock 305 tbi heads are junk, dont spend a dollar on them.

 

I wish I could put a 350 in it, trust me! The only reason Im going with the 305 is cuz my buddy is selling it to me rebuilt and ready to roll for $75. On my beer budget, I cant complain. I just want to get this car going so I can use it for my daily driver and let my wife use my 93 Z to haul the baby and go to school as well. Trust me, if I was to build this car like I wanted, a 305 TBI would not be anywhere near the top of the list (no offence TBI guys, much respect!). Also, the 305 Im getting wasnt originally a TBI, so the heads shouldnt be as bad on it. Or does the 305 just flow sucky with a TBI system on it? Either way, Im kinda stuck with it, so Im gonna have to make due.

 

Do you have any idea what the motor was in originally? Most factory 305 heads weren't very good, but some are better than others.

- Justin

 

Hey fellow Texan,
I might have a deal for you. I have an '89 TBI 305 that will be replaced shortly by an LT1. The heads on these motors are ABSOLUTE junk as someone stated above. My car has VATS, and that is a PITA. I don't know what your time frame is, but I'll give you the parts you need/want for cheap. I live in Alaska now, so shipping would be the major cost involved. My motor will be nothing but a boat anchor when I pull it, so you're welcome to the intake/TBI unit/harness, etc., etc. My car is tired-used and abused by some kid I saved her from. I'll more than likely park her in the next month or so and drive my beater Honda until the swap is completed. Once it's parked, you can have what you want-I figure $100 plus shipping is fair. Just PM me if you're interested.
David
BTW-Yes, I'm new to the site, but I'm not looking to rip anyone off. If you want the parts, I'll be more than happy to give you my home/work #'s, address - home/work, pet's name, etc.