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Difficulties of Chnaging to Carb from TBI

Discussion in 'The Garage' started by Big Red, Dec 14, 2004.

  1. Big Red

    Big Red 1/2 ton status

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    Hey all, i'll soon be building a 383 but i was wondering how hard it will be to switch from TBi to carb. How much will i have to modify the Wiring Harness? Will It be difficult to hook up the kickdown from the 700r4? (i may be chnaging to a th400, as my current 700r4 and Xfer case are held in wit helicoils eep!! ) I know the stock tbi wont handle the 383 im gonna build (S/R Torquer heads, Hedman or Hooker Headers, lots of power, lol) Any other opinions are gretaly welcomed!! Thanks you guys!!
     
  2. Wingnutt

    Wingnutt 1/2 ton status

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    The stock unit will definatly hold the engine back, but one from a 454 or a Holley 670 *should* handle it...BUT you will either have to learn how to burn your own chips (really not that difficult, if I can do it you can too) or find a GOOD tuner who is willing to spend the time needed to get yer engine running right. I'n not even going to go into the legalities of trying to register your vehicle or passing a sniffer inspection if your state has one because you will basically have to bypass the entire engine management system.

    If you think that I'm against changing over to a carb, your right. Personally I think that if you have a balanced system tuned to take full advantage of the engine, you will make more power and better fuel mileage than with a non-managed, carbed engine. Yes it take MUCH more time, but I think if you stick with it, you'll be plesently surprised.

    Oh yea, one more thing, you can always go with Edelbrock's bolt on MPI system that simply plugs into your current computer harness and just uses the TBI as a giant butterfly valve.
     
  3. Big Red

    Big Red 1/2 ton status

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    Thanks for the info. I would much rather go the Edlebrock Pro-Flo EFI (the regular efi is said to be rated at 350hp max, which i plan to push at least 400) Obviously i've changed my idea to go and save the cash for a B&M built 700r4. or i may decide to change my OD days and go with a 400. Hey, heres an idea, my dad just got a 7.2mp digital camera...i suppose i'll take pics and make a bit of a documentary about it no? lol. thanks again.
     
  4. 70jimmy

    70jimmy 3/4 ton status Premium Member GMOTM Winner

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    If you are serious about wanting to go to a carb from TBI let me know because I want to do the opposite. Maybe we can work a swap. I have a 2 year old Edelbrock 600 on a performer manifold. They were put on my truck when they were about 6 months old and my truck has been down for about 1.5 years on a resto mod.
     
  5. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    I dunno bout computers but I took a 1991 caprice police 350, took the TBI off and put a 1987 camaro z-28 intake on (yes I drilled the 4 center bolts... but dont tell anyone... shhhhhhhhhh)... my old 78 distributor and a new holley truck avenger... she is runnin great now.. (Since I have been adjusting the carb)
     
  6. beater_k20

    beater_k20 Banned

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    no offense, but those are not hardcore performance parts. the S/R in S/R Torquer stands for "STOCK REPLACEMENT" and headers have been mainstream mods since the 50s. i dont see any reason why your TBI wont put up with it, may need a bigger TB, and some tuning. for an engine that makes more power, gets better milage, and performs better on inclines, i dont see how anyone could even consider going for a carb over EFI.
     
  7. Emmettology 101

    Emmettology 101 3/4 ton status

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    I'm running a 89 3/4 with a 383. It has a Scat crank, manley rods, KB Hyeru pistons, Trick Flow Twisted Wedge heads, Comp Cam, etc.. It was built with a TBI on it originally. Then it was switched to a Carb.... I bought it this way. I siwtched it back to a stock TBI system with a Holley 670cfm and there isn't much difference. I am still running the stock chip... I'd stick with the TBi and find someone to burn you a chip, or do it yourself.

    I am working against a few odd variables with my app though.. I dont know what the comp ratio is(or if there are flat tops pistons or what) or what cam is in it. :( The builder never really filled my friend in and he didn't keep records. *shaking head* I know the comp ratio is through the roof. With the timing retarded and running 94, I still get pinging. :(

    One of these days I'll get around to pulling it and opening it up. But I would never switch back to the carb.
     
  8. fad2blk99

    fad2blk99 1/2 ton status

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    I went from TBI to carb once before also. I regretted it. There is nothing like stalling as you are trying to climb an obstacle. It’s not just frustrating; it’s dangerous as hell when you lose brakes and steering high atop a hill. My current Blazer has TBI and it will stay TBI (or some other form of fuel injection). On one of my last outings I had the truck almost completely vertical (my license plate was bent out 90*) and no hint of stalling what so ever… I’ll never run a crab again!
     

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