92 4.3l tbi to 5.7 carb please help!!

[denley]

ok i am new to all this, i tried to search but couldnt find anything specific. i am doin a 5.7 carb in a 92 sonoma 4.3 tbi wit 700r4 tranny. not looking to do much performance mainly doin it because i got a free motor and accesories. i hear it is not too easy of a swap, what all would need to be done besides new mounts, exhaust mani, and gas tank mod to get this thing swapped. please guide me as i cant find much on goin from tbi to carb thanks

[5.74x4]

off hand all i can think of is a fuel pressure regulator to regulate your tbi pump down to the pressure a carb needs and chopping out all the efi wiring. Is your free engine a tbi engine? if so I would run A tbi 5.7 since your 4.3 harness is the same as a 5.7 tbi. You'll need to swap some sensors,injectors,and the chip in the ecm but that's easy stuff. I'd also recommend buying the JTR swap books and read up on the swap.

[denley]

no my 5.7 is carb, it was free along with a holly carb, shorty headers, aftermarket fpr, ect. so all i need off hand is the mounts, exhaust mani, gas tank mod, fpr, and to chop the wires? but keep the alternator, ign, speedo, ect wires?

[The Griff]

What gas tank mod are you talking about?

[denley]

ive read that you need to take out the fuel pump out of the gas tank on the swap from tbi to carb and do some sort of mod with an inline pump and fpr. i really didnt understand that too much, but can anyone give me a summary of what i might need for my swap im real anxious to get it done.

[The Griff]

I didn't all I did was unhooked the stock intank pump and hooked up a mechanical fuel pump. Or you can just get a fuel pressue regulator and use the stock in tank pump, that's what I did for a few months.

[denley]

ok thanks, do i need to get a special radiator, headers, and any other components?

[denley]

any help guys?

[junk racing]

I removed the stock pump from my tank, used a piece if fuel hose clamped too the inlet where the pump used too connect for a pick up, too me leaving the stock pump causes a restriction on higher powered vehicles. I ran a holley blue pump with a bypass regulator also. You will need swap mounts, headers, im not sure about oil pan i have an aftermarket on mine, 4.3 radiator will work, electric fans unless you cut the radiator support to fit the radiator down in it. I think that about covers it

[Towmanred]

Quote: Originally Posted by denley

ok thanks, do i need to get a special radiator, headers, and any other components?

You can use headers or manifolds.. You can get the swap headers for less than 150 usually.. You can get creative with the radiator.. I'm using one from a 84-89 Vette (most guys do). For my fuel pump i bought a 20 dollar Holley regulator and i'm using the stock pump. Hope this helps..

[denley]

ok thanks, will i be able to use the 700r4 auto tranny out of my 92 sonoma on this 5.7l carb? how will the transmission shift without the computer? thanks

[swobecky]

i dont believe that tranny is connected to any computer... if im right, it should work just fine

[Drumer919]

700's arnt computer controlled but you will need to do something about the lockup converter. Plus you'll need to somehow get the TV cable hooked to your carb, I'm sure about every company out there makes a bracket for that though.

[denley]

ok thanks, what kind of problem with the convertor lockup will i have?

[denley]

bump

[denley]

any other help guys? im bout to rip out the 4.3 and send the tranny off to rebuild. i know i need 2.8 mounts, conversion headers, 84-89 vette radiator, twin cooling fans, tv cable bracket, and i still dont know what i need to do bout the convertor lockup. any thing else that would make this swap easier? thanks

[The Griff]

http://700r4.com/faq/computer.shtml

[denley]

ok thanks, so before i rip this out, the 700r4 tranny and driveshaft out of my 92 sonoma will 100% bolt up to my carb 5.7 no problems?

[The Griff]

Right, the bellhousing bolt pattern is a direct fit.

[denley]

awesome! thanks guys im gonna rip the 4.3 out this week.

[The Griff]

Do it tonight!

[denley]

i wish lol

[The Griff]

took me about 2 hours to pull mine. Just sayin..

[denley]

yea i got alot of my harness and vaccum lines unpluged from my 4.3, since im goin from tbi to carb what wires will i need to keep?

[denley]

what wires will i need to keep and connect for the 5.7 carb?

[Revolt]

Aside from the starter/battery and alternator wiring, gauge wiring, you need a wire to power your ignition coil from your existing harness (should be a pink wire hot in run and start). Then simply power your fuel relay/pump with a wire.
Really simple, however sometimes its easy to over think the simple. I've done it.

[denley]

ok thanks, i have the motor out and am ordering all my conversion mounts, headers ect. i do have a question about cooling. i have heard many using the ford taurus fans, i have found a set local from a taurus sho which is an offset dual fan setup. is there anyway i can use these with a superior radiator in the forward position with no clutch fan? also will be using a 180 thermostat. thanks guys

[Arich0908]

You do know for installation ease you can keep the tbi unit and run you engine with it.It bolts up with a adapter.
Just wanted to let you know you had that option if you did not know.

[denley]

wouldnt i need a ecu from a silverado then?

[Arich0908]

Quote: Originally Posted by denley

wouldnt i need a ecu from a silverado then?

Are you asking me ?

[denley]

thats usually why people use a question mark at the end of sentences. lol but seriously i would much rather have tbi anyone got more info on how i can keep it?

[Arich0908]

I do , Just take the ECM out of the car/ truck the 350 tbi came from. remove your ECM and it Plugs right into your harness. Boom thats done and easy huh?
Take the TBI that went to the V8 and use that since the injectors are different from the 4.3 TBI , unless the V8 tbi was acting up for some reason. Then just swap the injectors into the 4.3 tbi. They are the same unit, they just use different injectors.
Alll the sensors are the same also they will all plug right back in in the same locations. So save all the left overs you may need them some day.
As this ride your swapping the engine into 2x4 or 4x4 . If its 2x4 you can use any pan but if its 4x4 you have to use a specific swap pan and headers for clearance issues .
When you set the motor up you will set it up exactly like you would set up your 4.3 TBI model motor .

As far as I read you can use your stock radiator , all you accessory brackets bolt right up. So the from accessory from the 4.3 will go right o the 350.
The starter fits also.

This is what I plan on doing for ease of installation.

[denley]

well the 350 i have is originally carb not tbi, so will all the stuff still trasfer?

[Drumer919]

Yes, you need to use the knock sensor from the 350 though, and it its a 93 or older harness you will need the 5 wire, firewall mounted, knock module/spark control thing, what ever you want to call it .

[Arich0908]

http://www.tdperformance.com/products/?id=3225
This lets you bolt your tbi to a carb intake.
Go to a Junk yard get the TBI computer from that year along with the injectors and youll be good the rest will bolt up.