Vortec heads on a 5.7 TBI

Discussion in 'Chevy Truck Forum' started by MI0706, Apr 29, 2008.

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  1. MI0706

    MI0706 Well-Known Member

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    I have a 1992 Blazer (full size version) with a 5.7 TBI. A friend of mine says that I can change out the heads on that motor and go with some Vortec heads (should raise my horse power, according to him, by about 60-70 horse). It is also my understanding, that if I do this, i will also have to change my intake manifold.

    Just a couple of quick questions for you guru's out there...

    1. Will there have to be any computer modifications (chipset change, all new computer, etc.)?
    2. I can't find to much information about this on the net. Does this modification justify the cost?
    3. Does anyone know of a website, book, etc. that explains how to do this modification in detail (I would need something like a Haynes in order for me to do this modification)?
    4. Is there a complete kit out there (heads, intake, etc.) in order to do this modification? Or does one have to buy all parts needed separately?

    Ok... Ok... so it was more than just a "couple of quick questions"... ;)
     
  2. 03chevy

    03chevy Senior Member

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    as far as 60-70 hp. no unless you put bigger valves in it. just like you can to your heads you have. and yes you have to buy a new intake to fit the vortec heads. no comp. changes you need. you can look at summitracing.com or ebay.com and a few others to look for kits or separat pieces everybody has diff. prices. but my opion is why do all that when you can have your heads reworked with 2.02 valves a diff. cam, and a curve kit in the dizzy. and you will have more at a cheaper cost. just don't take my word for it look or other people to chim in on this.
     
  3. Sneakysportsman

    Sneakysportsman Senior Member

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    In all actuallity you don't have to change the intake. Save yourself a **** load of money and buy a dual bolt pattern set of heads or drill and tap your own heads. I did it and have had no problems. I sold a TBI-Vortec intake and you will have to buy a chip and turn off code 32 or externally plumb an exhaust return back to the front of the intake. OR install a set of 96 -99 Vortec exhaust manifolds with the return bung already in the manifold. OR you can buy a Carb intake for Vortec heads and get a TBI-Square bore adapter. I have one of those I need to shed.

    If you drill and tap your own heads, you only have a fine line to get the intake center.
    When you drill the 4 outside bolts you will drill thru the water jacket, no problem, when you install your intake bolt coat the threads with black or gray sealant. Also, in order to drill deep enough you may go thru to the original bolt pocket. If you do Plug the Original bolt sockets with allen set screws and some black or gray sealent.
    You may also have to slot the outer bolt holes in the gaskets, in order to move the gasket up the head to get adequate sealing pressure and runner seal and coverage.

    Enough for now, If you have any questions PM me And I can go further into detail. It sounds like a lot of hassle but with a little time and patience it can be done very easily.
    One more thing, If you are putting Vortec heads on an old block, it is only a matter of time before you blow out the bottom end. BECAUSE TBI heads are 76cc and depending on what Vortec heads you get some are 58cc and some are 64cc.
     
  4. Sneakysportsman

    Sneakysportsman Senior Member

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    There is ONLY ONE complete TBI upgrade kit. It is from Edelbrock. Visit their website and they will give you specifications. There is ABSOLUTELY NO CAMS on the market that are bolt in for a TBI engine. Even the smallest that Edelbrock makes requires a chip change. Edelbrock Cam #3702. I have every availible TBI "BOLT ON" part on the market. I have "Computer Compatible cams" that did not bolt right in. I have the joke 52mm throttle body. The only way this will help performance is to have the intake bored to match it. The engine will only displace as much as the 1 11/16 throttle bores will allow. You can PI$$ your money away on external bolt on parts, you will spend more than you want, with no noticeable difference.
     
  5. NHEngineer

    NHEngineer New Member

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    Great advise you guys are giving. I've started in racing in 1961 but I've been on the sidelines for so long I've lost the thread so to speak. I just started running "Outlaw" Sportsman stock car in New England. I'm researching an innovative motor induction concept. How can I put a TBI manifold on Vortec heads? I've found a guy who will make an adapter for a 4412 Holly to TBI for $100 so my next problem is to put the TBI manifold on the Vortec heads. The TBI heads have vertical [almost anyway] intake mounting screws. Will things match up with the Vortec heads?

    Yup, I know this is a truck forum but you guys are way ahead of me with your technology. I'd like a chance to catch up.
     
  6. inthechateau

    inthechateau Member

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    Vortec heads and TBI

    Your biggest problem will be bolt patterns. If I recollect right the TBI intakes are still 10 bolt and the vortec heads are only 8 bolt. Square me if i am wrong......
     
  7. bradrhale

    bradrhale Senior Member

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    [​IMG] 04-29-2008, 06:05 AM

    i have noticed a rash of old threads being brought up. 2 years later, i doubt he still has this problem on his plate.
     
  8. thegreenfortnox

    thegreenfortnox Full Member

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    swapping out the heads for newer vortec heads will not get the performance your looking for especially the cost of doing this swap and time. if your looking for performance from a tbi the best way to do it is to take the fuel injectors off the tbi and take it apart and adjust the internal regulator to feed more fuel or put a bigger cam. but changing the heads will definatly not get the performance your looking for, you will get way better gas mileage slightly. but no matter what, its still pretty much a carburetor all said and done.. it doesnt airate the fuel very well.. good luck--
     
  9. wyochimneysweep

    wyochimneysweep Senior Member

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    install tpi
     
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