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Tbi to carb conversion
#706547 April 05th 2016 11:26 pm
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So, i've been gone for awhile taking care of work and getting thins settled trying to figure stuff out. on my 92 g20 350 is old and tired, burns more oil then fuel these days, so i did what a good owner would do...

i bought a 350 engine off craigslist with corvette heads, performer intake. Holley 600 cfm double pumper. it had a huge cam in it that would require me to change the torque converter, didn't want to have to do that so i got a crowler torque beast cam to put in it.

i tore down the 350 and measured all the bearings, checked the rods and pistons, made sure the cylinders where alright before putting it back together. took apart the heads and found a broken spring that i replaced. seals where in good shape so i left them alone, valves where decent so i left those alone too. i let the heads run through a parts washer a few times before putting them back together.

this weekend i am tearing out the old 350, going to look in to resealing the transmission and getting it ready to install the new 350.

so has anyone else switched from TBI to carb? i'm not 100% sure of all that is involved. i know the 700r4 in these need the cable to insure proper shifting, and I've read that i need to get a kit for torque converter lockup.

at this point im just trying to figure out everything i need to do, sort of a to do list of parts and components.

i do already have a bypass regulator for the carb.

the transmission is what i'm really worried about though at this point, i was offered a turbo 350 trans to throw in it but i realy like my overdrive, so i hope someone here knows what i would need to do other than just throwing a carb at it lol.

Re: Tbi to carb conversion
SonnyLada #706597 April 06th 2016 6:14 pm
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you should be able to leave the tbi system from the van intact and bolt it to the engine. if you are using a carb, holley makes an adapter for the throttle linkage side that provides the right geometry for a 700r4 tv cable. as for the torque converter lockup, you simply need to make a relay ciruict that provides power for the system to work. I did a simple search online, here is a link that seems thorough enough http://www.crankshaftcoalition.com/wiki/Torque_converter_lock_up_control_700R4

if you go to monstertransmissions.com they sell some different kits and have youtube tutorials. I will say that the tv cable mount to block adapter is eh... but the adjustable cable they sell is great for most all aplications.

If you need any other help with it send me a message, I have installed a lot of these systems on many different vehicles, most recently a 350/700r4 setup in a 86 jeep cherokee.

Re: Tbi to carb conversion
SonnyLada #706625 April 07th 2016 12:07 am
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sounds good. this comming weekend i am tearing out the old engine to rob parts and make way for the new one.

Re: Tbi to carb conversion
SonnyLada #706639 April 07th 2016 8:54 am
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Iv done this to my 92 2500 vandura. Speedometer still works with computer and unnecessary engine harness removed.

Re: Tbi to carb conversion
SonnyLada #706671 April 07th 2016 3:42 pm
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I am keeping the engine harness intake just in case I want to switch back to tbi in the future. for now I want to be carbed for easy tuning, been wanting to hot rod around town with the van for a long time.

Re: Tbi to carb conversion
SonnyLada #710559 June 25th 2016 6:51 pm
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Why in the world would you want to go backwards?


2004 Ford E250 5.4 4r75w dana 60 with 3.73;'s (Current)
1992 Dodge B350 360/46rh non lockup /9.25 rear with 3.90 cogs (sold)
1986 GMC Vandura 2500 305/TH350/3.08 rear (Sold)
1994 G20 Ex Virginia DOT crew van 305/4l60/3.42 G80 10 bolt (Sold)
1969 Chevy G20 Sport van 230,3 on the tree, 12 bolt with 4.11 cogs.(Sold)
2004 Chevy Express 2500 4.8,4l80E,3.73 (sold)
1990 ford e250 club wagon 460.E4OD,dana 60 rear 4.11's (sold)
Re: Tbi to carb conversion
SonnyLada #711053 July 07th 2016 3:59 pm
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Because TBI is the worst invention ever. My 91 Chevy was a slug with TBI. My 83 GMC, same van same engine, Rochester 4bbl would eat if for breakfast.

Another choice, which I did on another 90s Chevy Van is to go tuned port. I got a complete setup from a Trans Am. It was like night and day. Just make sure you match the computer to your engine and trans.


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Re: Tbi to carb conversion
SonnyLada #711070 July 07th 2016 6:14 pm
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J
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I have an 86 with a 305 4brl and its not much more powerful than the TBI 305 I had in my 94 , but The TBI damn sure ran better.


2004 Ford E250 5.4 4r75w dana 60 with 3.73;'s (Current)
1992 Dodge B350 360/46rh non lockup /9.25 rear with 3.90 cogs (sold)
1986 GMC Vandura 2500 305/TH350/3.08 rear (Sold)
1994 G20 Ex Virginia DOT crew van 305/4l60/3.42 G80 10 bolt (Sold)
1969 Chevy G20 Sport van 230,3 on the tree, 12 bolt with 4.11 cogs.(Sold)
2004 Chevy Express 2500 4.8,4l80E,3.73 (sold)
1990 ford e250 club wagon 460.E4OD,dana 60 rear 4.11's (sold)
Re: Tbi to carb conversion
SonnyLada #711079 July 07th 2016 9:43 pm
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If your running a Holley, you need both pieces. I once bought the throttle bracket and under the advice of the seller I was told I didn't need the bell-crank adapter. At part mid throttle It wouldn't up-shift untill about 4 grand, I guess he thought I lived at the dragstrip . I got the other piece and everything was peachy. Don't be afraid to use aftermarket OE replacement cables, they are simple and last as long as the OE. Try Pioneer Auto inc., Search and pick your part. Pick the cables for carb app. I can buy both cables over here for around 40 bucks, maybe a little more in Alaska. If you have a earlier tranny the lock up is mechanical and you can get away without the kit, mine came from a 85 Caprice and the fluid is bright red. 700R4's came with a high stall converter, they have been known to slip as high as 1800 rpm. Why switch to carb? even today there is no replacement for the crack of the whip from a 4 bbl. unless you got 1200 laying around.

Re: Tbi to carb conversion
JIm Rockford #711158 July 09th 2016 1:54 pm
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Originally Posted by JIm_Rockford
I have an 86 with a 305 4brl and its not much more powerful than the TBI 305 I had in my 94 , but The TBI damn sure ran better.


Can't judge anything by a 305, or as we used to call them, anchors.

In all my years owning and working on GM vehicles, I never found 1 TBI equipped vehicle that could outperform a carb equipped vehicle. Also, a carb can be adjusted and fine tuned to your liking, a TBI is set one way and aside from spending lots of money on injectors, computer chips or other nonsense, you can't adjust them.

Just about the only downside of a carb is, you need to let it warm up. I even got around the remote start problem by installing a small solenoid that would pump the gas pedal before cranking. I used to hear all the time how you "can't put a remote start on a car with a carb".


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Ripper

Serving NYC/LI
347-303-7403
Re: Tbi to carb conversion
SonnyLada #711608 July 18th 2016 11:27 pm
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check out a member on Thirdgen.com named fast355 I think he was on here too, tbi can be tuned same as a carb , and they love a 2brl victor jr. single plane intake.


2004 Ford E250 5.4 4r75w dana 60 with 3.73;'s (Current)
1992 Dodge B350 360/46rh non lockup /9.25 rear with 3.90 cogs (sold)
1986 GMC Vandura 2500 305/TH350/3.08 rear (Sold)
1994 G20 Ex Virginia DOT crew van 305/4l60/3.42 G80 10 bolt (Sold)
1969 Chevy G20 Sport van 230,3 on the tree, 12 bolt with 4.11 cogs.(Sold)
2004 Chevy Express 2500 4.8,4l80E,3.73 (sold)
1990 ford e250 club wagon 460.E4OD,dana 60 rear 4.11's (sold)
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