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Edelbrock MPFI or Holley 670 CFM TBI

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by Madbomber88, Mar 14, 2005.

  1. Madbomber88

    Madbomber88 1/2 ton status

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    I'm just curious what everyone thinks is the better bang for the buck.
    I'm debating them both for a stock 91 K5 that has to pass strict emissions...
     
  2. sweetk30

    sweetk30 professional hooker Premium Member

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    well you just said emmisions tests and need to pass best leave alone so no problems , but thats just my opinon. i am going to install the edelbrock setup proflo on my moms old 73 mustang soon and its nice and profesinal looking setup . will post more as it comes along.
     
  3. nevada88

    nevada88 Registered Member

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    Tried the Holley

    I replaced the stock unit on my 88 with the holley. The upper end was great, a noticeable power increase, but driveability sucked. The truck loaded up, would stall and even backfired when cold. From the other posts that I have seen the holley notoriously runs rich. Haven't returned it yet cuz i sure liked that upper end. Curious if anyone else had the same experience.
     
  4. Thunder

    Thunder 3/4 ton status

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    If I had a choice between the 2. I would go with Edelbrocks Performer MPFI for TBI. it is a direct bolt on and is 50 state smog legal. It even uses the stock TB after the injector pod is removed. Should pass even the strictest emission tests.
    And have great driveability.
     
  5. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    He did say bang for the buck. I would say that a $350 TBI unit on a stock engine with maybe a couple mods to it is a far better bang for the buck than a $1000.00 MPFI unit. Don't get me wrong, the MPFI would be the best thing if the engine had other mods such as a bigger cam, headers, and ignition.
     
  6. mini_mull

    mini_mull 1/2 ton status

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    I don't have any personal experience, but if you do a search for "holley throttle" it pulls up a lot of problems people have had with the Holley 670 cfm. If I understand correctly you most likely would need a custom chip to overcome the running rich problems that it has on a stock engine (which would be bad for emmissions if left alone). I remember reading some other people have had problems hooking it up because although it's called a direct replacement but some of the throttle cable hookups and such are a little different plus there's no where for the CC you have to fab something up. It also uses different injectors than the typical GM injectors, I believe I read they use the mopar ones, but check for yourself I could be wrong. I've been researching the different sftermarket throttle bodies to find what would go best with a HT 383 swap. If you don't want to spend the whole enchilada on the edelbrock system you might check www.turbocity.com or www.cfm-tech.com They have modified stock throttle bodies, and performance packages, there are a lot of guys that swear by them. I'm considering their vortec package for the HT. Sorry I don't have any personal experience to share, but I've spent a lot of time searching and researching so I thought I'd at least share some of what I've found. Good luck, and let us know how it goes, I'd love to read about someone who went with the holley and didn't have any issues, but I haven't found anyone yet.
     
  7. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    The holley 670 CFM TBI is nothing more than a BBC TBI. I don't know if the holley 670 comes with injectors or if you are supposed to reuse your old ones but here is what i'm about to do. I picked up a factory BBC TBI and i had my intake manifold throttle bores machined to except the larger 2" throttle bore of the TBI unit but i'm going to use the factory 350 injectors since the BBC injectors would be too large on a 350. The 02 sensor will pick up the fact that it is running too lean since there is more air now compared to fuel and it will richen the micture as needed. The stock injectors do not work to max capacity so there is room for the extra fuel that would be required by the extra CFM of the larger TBI. :thumb:

    Also, i already know i will need to modify the throttle linkage plate since BBC's never used a 700R4 tranny from the factory and there is no provision for the TV cable to hook up too.
     
  8. 70~K5

    70~K5 1/2 ton status

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    Scott, what would be the best bang for the buck to improve a stock '95 7.4L TBI?
     
  9. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    I would start by installing the air flo enhancer #630-110, injector pod spacer #630-105, adjustable fuel pressure regulator #630-130, all these item are sold by turbo city.
     
  10. Thunder

    Thunder 3/4 ton status

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    Ok guys so some one tell me how a Holley 670 TB Has it all over a Edelbrock MPFI..... HMMMMM....... I am listining...... Can you guarenteey it will pass smog :grin:
     
  11. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    MPFI is far superior to TBI but he was asking about bang for the buck as well as smog legal, the MPFI is 50 state legal but IMO the price does not justify itself on a stock engine like a larger CFM TBI unit does.
     
  12. Madbomber88

    Madbomber88 1/2 ton status

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    So what you area all saying is that the Holley is the best choice as the only mod to a stock engine, but the MPFI would be better if it went on with headers, cam, and intake?
     
  13. 70~K5

    70~K5 1/2 ton status

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    No the MPFI is the better choice, but pricey. :xmas:
     
  14. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Bruce, on a stock engine and bang for the buck the holley would be best. The MPFI would be much better on an engine with other mods.
     
  15. Jonny-K5

    Jonny-K5 1/2 ton status

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    i've got the holley 670 on my stock 89, doesnt have any real driveability problems, besides a slighter stronger exhaust smell at the tailpipe. passed the smog test w/ flying colors.

    i didnt really see any performance gain from going with the holley. i think the money would be better spent doing the stock tbi upgrades, such as an adjustable fuel pressure regulator w/ gauge,1/2" spacer,injector spacer,etc.
    the factory tbi flows plenty for a factory stock engine, just needs to be tweaked a little.

    the mpfi conversion would be cool, but that is kinda expensive. i think best bang for the buck would be the mods i've suggested.i do think the holley would be a good upgrade with a better motor, maybe a 383, or a fresh 350 with good heads and cam. thats the main reason i'm keeping mine, to use on a more powerful motor that needs the extra air/fuel.
     
  16. 70~K5

    70~K5 1/2 ton status

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    For the money maybe, But if any TBI was better why did Chevy spend the extra money switching to TPI on "stock" engines?
     
  17. mini_mull

    mini_mull 1/2 ton status

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    Jonny-K5, did you have any difficulties when you installed your holley? Anything you had to modify or hook up differently? Did you adjust your fuel pressure? I think this is enough on topic that I'm not thread hijacking, if not, pm me instead of posting. Thanks, I'm trying to decide whether to go with the holley or the turbocity package. I'll be putting it on my stocker for now, but will be swapping to a 383 later. You sound like you like your holley, and I've never read about anyone on this board being totally happy with theirs, so I'd love to hear about it.
     
  18. 4X4HIGH

    4X4HIGH 1 ton status Premium Member GMOTM Winner

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    Bruce, maybe you did not see this response that i made early on but here it is again.
     
  19. 70~K5

    70~K5 1/2 ton status

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    Scott, We're saying the same thing. For the money on a stock engine the Holley is better. But over all the MPFI is a better setup. And once you start how many of us stick to just 1 mod to our engines?
     
  20. Jonny-K5

    Jonny-K5 1/2 ton status

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    lets see, i didnt really run across any problems. i installed it causs it came with the truck, the PO bought it hoping for better part throttle power, but
    never got around to putting it on. he said it did have the wrong sensors installed, and he had to screw around quite awhile trying to get the right parts from holley. thats probly why he never got around to installing it.


    i didnt adjust anything, except the TV cable. oh and the vaccum lines didnt fit. ports arent in the stock arrangement, so some of the lines were too short

    if i could do it all over , i probly wouldnt use it. no need on a stock motor.i think i would have had better results by tweaking the fuel pressure and gettting some hop ups for the stocker.

    if i was swapping in a 383 like your doing, i might consider it, a tweaked stock tbi might not flow enough, im not sure tho. im no expert in this subject but i think for a 383, or a 350 with good heads and cam, the holley unit is the hot ticket if keeping the TBI system.
     

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