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Has anyone used the Holley 2 bbl OEM replacement TBI (Pro Jection)?

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by mplogic, Mar 20, 2003.

  1. mplogic

    mplogic 1/2 ton status

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    I recently did an engine swap. Used a 400 block bored .040 over (409?) and my stock 89 heads and intake. I've got the bottom end taken care of, but am looking at ways to open up the intake without the big expense of a TPI or MPI setup. The specs on those Holleys say they flow like 20% better than a stock TBI and they cost about the same as a new carb (around $370). Was wondering if anyone had good or bad experiences with them. Also considered the 4 injector model but then have to change the manifold and more and for that price I'm pretty close to a nice aftermarket MPI setup. I probably need a reprogrammed chip too but want to get everything else finished first. Hmm, what to do, what to do?
     
  2. BowtieGuy3

    BowtieGuy3 Guest

    I don't have any info on them, but I'd like to hear how it works out for you. I'm in the proscess of converting an engine I have over for use in the truck, and it's no where near 400 cid. Also, Where did you find the 2bbl TBI for $370? I've been looking around for them and haven't seen anything lower then $450...
     
  3. DukeBoy88

    DukeBoy88 1/2 ton status

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    I have one, the 670cfm 2-barrel. I used it on my relatively stock 350, with a generic accel chip. It came with a reducer plate that mounts between it and the manifold. I used the plate instead of opening up the manifold. My truck /forums/images/graemlins/k5.gif is currently tore apart with the 350 out and not going back in. I plan on installing a HT383 and opening up the manifold to accept the larger throttle bore size. also plan on having Ed wright program a chip for my application. (He programmed my trans-am, he does very good work) I'll have to let you know how everything goes.
     
  4. Chris Demartini

    Chris Demartini 1/2 ton status

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    <font color="blue">Those heads and intake will be too restrictive. What size cam are you using?
     
  5. mplogic

    mplogic 1/2 ton status

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    Thanks for the feedback guys.

    Jegs has a really good price on it here:
    http://www.jegs.com/cgi-bin/ncommerce3/ProductDisplay?prrfnbr=1522&amp;prmenbr=361

    It's just a drop in replacement that uses the factory wiring and computer. The kits with ECU are much more expensive.

    The cam I'm using is a mild Comp dual grind

    Valve lift: Intake .447 Exhaust .454
    Duration at .006: Intake 256 Exhaust 268

    I didn't want a high revving horsepower monster, more of a low end torquey beast. From what I've seen the stock TBI manifold is far less restrictive than a typical stock carburator manifold, although it probably will hold me back a bit. Also, these 89 heads are identical to the 400 heads (which were bad). The only difference was the lack of steam holes which we had the machinist drill out.

    This is my daily driver too so I don't want a screamer, but I don't think I'm getting too much out of the higher ci with a totally stock intake either. That was basically my question, will the bolt on Holley TBI give me a slight increase in flow with the stock manifold and heads or will there be no difference at all over a stock TBI?
     
  6. BowtieGuy3

    BowtieGuy3 Guest

    I know Holley claims their TBI replacement does flow more then the OEM unit. And I know Holley, and I believe Edelbrock has Intakes for the TBI application. You should get more performance out of it, but would need the intake and reg performance mods later down the road to see any major gains. If you REALLY want to be sure, bring the truck to a chassis dyno after each mod you make, that way you can see where the gains are.
     

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