1992 pontiac firebird 305tbi/700r4

hey i plan on swapping out my 305 tbi to a 350 carb in my 92 firebird, i know how to deal with the tranny issues, like the lock up thing and what not, but what i need help with is what wires go where, which colors to use, and other wires that need to be used and not used, and any other info i should be aware of, i dont like running into issues cuz ill just junk it all....very impatient i am haha, thanks hope to hear from someone.

 

Welcome aboard thirdgen.org.

First, just to understand, is there a reason you wouldn't keep the TBI? It has several advantages over carb.

If you do swap to the carb, basically, everything you need can be separated from what you don't need. Keep your '92 accessories (alternator, water pump, power steering pump, air conditioning compressor), all of those wires go through the bulkhead connector on the driver side corner of the firewall. The ECM stuff you don't need can all be pulled out - remove the fender liner from the passenger side fender, you can see the harness bundle that passes through the body kick panel. Drop the ECM down, disconnect the connectors that go to the pass-through connector, unclip the pass-through connector, and pull that bundle out from the engine compartment. Disconnect/remove everything it connects to, and you're done. Leave the ECM connected and installed to everything else and your fuel pump will continue to work.

Your alternator, air conditioner, gauges, etc., are unaffected by removing the engine ECM harness. What distributor were you planning on using with the carb'd engine? If you are using a self-contained HEI, the pink power wire to the coil goes to the "BATT" terminal on the HEI, and the white wire to the coil goes to the "TACH" terminal on the HEI. Terminals are available to enable them to be clipped properly in place.

You'll have to use a return-style fuel pressure regulator like the Mallory 4309 to drop the fuel pressure down to a carb-friendly 4-6 psi. You'll need some adapters and hose to do that. There is a tech article linked from the thirdgen.org homepage (also linked in the Carburetor forum sticky "welcome to the carburetor forum") with more details on the whole EFI to carb thing.

 

i chose to swap to carb because of more horsepower and i love building up sb 350's, anyway i plan on using the regular hei dist., im throwing out the ac that takes up lots of hp, im guessing the purple and white wires out of the ignition harness is what i need to use on the dist.

 

five7kid wats your opinion on the 305 tbi, wat would be some quick upgrades, not really worried about cost but dont want to get drained, i was thinking bigger heads, cam kit, intake, and maybe injectors??? im not really familiar with fuel injected motors???

 

The TBI forum would be a better place to look/ask. But, I'd say not bigger heads, but better heads, like ported 081's with 1.94" intake valves. With an appropriate cam, better fuel pump, and maybe 350 TB, plus 100% exhaust upgrade, you can have a smile on your face. After PROM tuning, of course.

 

i personally like dealing with carbs

carbs are great for young guys like us who buy them cheap, bolt em on and go.
because later in the future you can use better parts with the carb to get more horsies
they need some tuning everynow and then but i enjoy that

 

i have a 91 bird i went from 3.1 multi port to a 350 carb i can probebly help ya with alot of difren things. i just did this to mine last week. pulled the gas tank and took out the electric pump and the wire to activate it. put a peice of steel line the same length in place of if with a high pressure fitting. now i run pump gas. i had the regulator set up before and had a switch to run the pump.... just got sick of all the switches so thats why i did this one mod. it works great , runs awesome oh ya before i forget... when you put the steel line in , keep the flared end at the bottom cause then you can clamp a screen on the end without the worry of it fallin off

 

all the wires are there to make it work like previously stated .. the only thing i ran into was i didnt need the power steering switch and i just had to change a few pigtails... mostly probebly cause i used a 77 motor... but the serp set i got from another guy here , bolted right on with the exception of one bolt on the bracket for the ac. but there was plenty of others to hold it up. also the brackets did clear the fuel pump on the block. i just ran steel line under the front of the engine to the pump and blocked off the return....i am lookin into getting a manual fuel pump with a return so i can utilize the option of having one

 

i did run into a few things i had to change but i cant think of all of them at the moment...if you do go with this swap and you run into an issue, let me know cause i may have had the same issue.... good luck