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TBI to carb/1991 C1500/350-383 buildup

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Old 05-07-2009 | 09:58 PM
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Question TBI to carb/1991 C1500/350-383 buildup

I have a 1991 Chevrolet C1500. I'm getting ready to build my 350, stroke it out to a 383 and im going carbureted. A lot of people are gonna say im stupid for doing it i know but i don't have $1500 to spend just to keep the TBI set up. (Ported throttle body, big injectors, ECM reprogram, and whatever else is required) Anyways, i have almost everything i need and im almost ready to pull the motor out and get started. Just wondering if anyone else has done this and what information can you give me to make this easier. Heres a few things that ive heard and i few things im worried about.

I was told i could use the stock fuel pump and put a fuel pressure regulator in with a return line. Is that true? Has anyone done this? If not, i was told a inline fuel pump can pull through the in tank pump, is that true? Will it flow enough fuel for my motor? I'm going with an edelbrock 750 performer carb.

Also worried about my gauges. Since i wont be running the ECU, will all my gauges still function properly? I plan on building a gauge cluster later on with some aftermarket gauges but don't have the cash right now to do so.

What about the wiring harness. How is it tied into all the power wires that run into the fuse box on the drivers side compared to what runs in on the passengers side for the ECM. I don't want to rewire the whole truck and im sure i don't have to. Are the wires just ran into the same wire loom, can i take the ones out for the ECM and separate them from all the power wires, gauge wires, and whatever else?

All help, info is appreciated. I'll keep you posted on what i run into during the build up. I plan on starting the end of this month and would like to have everything ready and put back in by the end of june. Money is the main concern now. Thanks for everything guys.
Old 05-08-2009 | 06:49 PM
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any ideas anyone?
Old 05-08-2009 | 07:24 PM
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Originally Posted by 1LowC-body
I have a 1991 Chevrolet C1500. I'm getting ready to build my 350, stroke it out to a 383 and im going carbureted. A lot of people are gonna say im stupid for doing it i know but i don't have $1500 to spend just to keep the TBI set up. (Ported throttle body, big injectors, ECM reprogram, and whatever else is required) Anyways, i have almost everything i need and im almost ready to pull the motor out and get started. Just wondering if anyone else has done this and what information can you give me to make this easier. Heres a few things that ive heard and i few things im worried about.



I was told i could use the stock fuel pump and put a fuel pressure regulator in with a return line. Is that true? Has anyone done this? If not, i was told a inline fuel pump can pull through the in tank pump, is that true? Will it flow enough fuel for my motor? I'm going with an edelbrock 750 performer carb.

Also worried about my gauges. Since i wont be running the ECU, will all my gauges still function properly? I plan on building a gauge cluster later on with some aftermarket gauges but don't have the cash right now to do so.

What about the wiring harness. How is it tied into all the power wires that run into the fuse box on the drivers side compared to what runs in on the passengers side for the ECM. I don't want to rewire the whole truck and im sure i don't have to. Are the wires just ran into the same wire loom, can i take the ones out for the ECM and separate them from all the power wires, gauge wires, and whatever else?

All help, info is appreciated. I'll keep you posted on what i run into during the build up. I plan on starting the end of this month and would like to have everything ready and put back in by the end of june. Money is the main concern now. Thanks for everything guys.
I have done it. Your stock fuel pump will work. You will need a return style fuel pressure regulator. Your oil pressure, fuel, and temp will work. Your cruise will not without some work. You will have to do some work on the wiring for the fuel pump relay. It is not hard. I will try to find a write up I did. If you have any questions you can email me mgbrent at gmail.com

http://www.fullsizechevy.com/forums/...carb-swap.html
Old 05-09-2009 | 06:05 PM
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thanks im going to start next month probly ill email you if i have questions, sounds like you have the same truck i do. what trans are you running? i also have a 1991 c1500 black stepside.
Old 05-13-2009 | 06:36 PM
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Why not just get the throttle body setup with injectors from a 454 engine and keep the TBI injection with the new 383? You will have better power and mpg but obviously you will need a custom chip for the computer which are usually cheap for those anyway.
Old 05-19-2009 | 09:14 PM
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Originally Posted by 85irocinjected
Why not just get the throttle body setup with injectors from a 454 engine and keep the TBI injection with the new 383? You will have better power and mpg but obviously you will need a custom chip for the computer which are usually cheap for those anyway.
custom chip is about $400 i already checked into all that. TBI maifold for vortec heads is about $300. TBI unit has to be ported. All that is the price of a stroker kit there. Injectors are about $50 (used on ebay so who knows if there good). TBI has to be modified with an adjustable fuel pressure regulator. All this vs a Edelbrock 750 4 barrel for less than $300 and a fuel pressure regulator for about $50. What would you pick? Its not a DD for me anyways i have a car for that. So MPG isnt an issure. This is just a street truck build and i have everything i need now for the carb cept the actual carb, fuel pressure regulator, and fuel lines. And i doubt you can make more power with a TBI than a 4 barrel carb unless you did spend some serious money.
Old 05-19-2009 | 11:03 PM
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I live in Hartselle and have done the swap. Actually I have since sold my 95 with a stock junk yard 350 in it and am looking to sell my 383 that is on the engine stand.
I left my computer in and hooked up to control the speedo and gauges (mine was a 5 speed). I used the electric pump and regulator ( I have one of those as well). I later went from carb back to TBI but my cam was too big for the slow *** computer to keep up and gave up after 51 custom chips and logging with a wideband.
Shot me a pm if you're interested in the 383. It's 10:1 224/232 114 lsa hyd roller, forged pistons and balanced assembly.
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