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Thread: Vortec Head swap on my '92 TBI 350. Tuning questions.

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  1. #1
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    Vortec Head swap on my '92 TBI 350. Tuning questions.

    New guy here! How y'all doing?

    Like the title states, I've got a 1992 GMC 1500. It's got the original 5.7 block in it, bored over to a 355, injector spacer, otherwise stock.

    Headgasket blew recently so I decided to do a Vortec head swap since she's ripped apart anyway. I've got the set of heads ready to buy locally, and this intake:



    It's a SUM-226018, square-bore Vortec intake to match the heads. Plans are to get a square bore carb to TBI adapter to essentially make it all bolt-on.

    Tore apart the motor and BOOM, discovered that it's been converted to a roller cam. Sweet! Bad thing is, I don't know the specs on the cam. BUT, I'll be going to a bigger cam anyway so she can breath better, so no issue there.

    So here's my issue, I've been told to fully get the potential power of the head and intake swap, I need a chip burned to bring it all together. Here are my specs:
    -Stock 906 heads, rebuilt, ported and polished.
    -above intake
    -Stock 350 (but roller cam) throttle body, injectors, and regulator, plus 1/4in injector pod spacer.
    -3.42 gears
    -31" tires

    What do you guys think? Do I need anything else, and as far as tuning, how close can we get to running good for daily driving? Could I just bolt the heads and intake on, and run it temporarily until I get the new cam in and tune it from there? Thanks!

  2. #2
    Super Moderator dave w's Avatar
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    I've tuned several Vortec heads with TBI conversions.

    I like the TBI adapter plate pictured below!!!

    The AE and PE needed for the Vortec heads is HUGE!!!

    The factory Vortec timing tables are a good place to start.

    15 lb TBI pressure regulator is a good idea.

    Injector flow of about 70 lbs is about ideal!

    Data logging is only way to know if the chip is working correctly.

    dave w
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    Some of the truck motors had rollers from day one.

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    Quote Originally Posted by dave w View Post
    I've tuned several Vortec heads with TBI conversions.

    I like the TBI adapter plate pictured below!!!

    The AE and PE needed for the Vortec heads is HUGE!!!

    The factory Vortec timing tables are a good place to start.

    15 lb TBI pressure regulator is a good idea.

    Injector flow of about 70 lbs is about ideal!

    Data logging is only way to know if the chip is working correctly.

    dave w
    I like that adapter plate as well! Got a link to where I could get one? And as far as the bigger injectors go, i was planning on doing a 65lb/hr police car injector setup with a 454 throttle body later down the road, what do you think?

    Quote Originally Posted by Fast355 View Post
    Some of the truck motors had rollers from day one.
    This one didn't. My uncle had it converted for some reason.

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    Fuel Injected! CDeeZ's Avatar
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    That's a nice looking intake. I've always wanted to try a single plane manifold with TBI. Maybe one of these days I will.

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    Fuel Injected! 1BadAction's Avatar
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    Nevermind, I misread the first post. Good luck with the project!
    Last edited by 1BadAction; 06-27-2013 at 10:30 PM.
    94 Blazer, Turbo'd 350 TBI - DD
    1991 2500 Suburban Adventure truck - 4wd conversion, 4-link F/R, 582ci CNP Big Block with Terminator X EFI backed by a 6L90 and twin stick'd NP205 t-case
    2012 Porsche Panamera Turbo - Date night car :)
    1979 16' Action Marine/"Johnny Cash" Merc Bridgeport Champ Motor - Metalflake Maniac

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    Quote Originally Posted by CDeeZ View Post
    I've always wanted to try a single plane manifold with TBI.
    Once you try it you will never use a dual plane again


    TOM
    1994 3500 Dually , 502 (509) , 264HR , Edelbrock MPFI , PFI '7427
    1992 S-10 434 SBC/Tremec - '7427
    1986 Monte Carlo SS
    1984 S-10 , SAS, 496/700R4/205 , D44/14BFF -'7427
    1980 Z-28 496/700R4
    1979 Corvette 496/700R4
    1977 Olds 98 Regency 403/700R4

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    Quote Originally Posted by CDeeZ View Post
    That's a nice looking intake. I've always wanted to try a single plane manifold with TBI. Maybe one of these days I will.
    Me too! But the only single-planes I could find for Vortecs were High-rise. Definitely not needed on my street truck :lol:.
    Quote Originally Posted by Nasty-Z View Post
    Once you try it you will never use a dual plane again


    TOM
    Well damn, maybe I should have looked harder! Haha. But i heard single-planes can mess with air/fuel distribution throughout the cylinders?

  9. #9
    Super Moderator dave w's Avatar
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    Quote Originally Posted by jdyates View Post
    Got a link to where I could get one? And as far as the bigger injectors go, i was planning on doing a 65lb/hr police car injector setup with a 454 throttle body later down the road, what do you think?
    I think the adapter I posted a pic of is available on ebay? I tried looking on ebay, but didn't find it. I'm using a 454 Throttle Body with the Cop Car injectors, good setup! My 5.7 has a roller cam similar to the Vortec roller cam, but I'm still using factory TBI heads with roller tip rocker arms and a modifed factory TBI intake.


    dave w

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    Quote Originally Posted by dave w View Post
    I think the adapter I posted a pic of is available on ebay? I tried looking on ebay, but didn't find it. I'm using a 454 Throttle Body with the Cop Car injectors, good setup! My 5.7 has a roller cam similar to the Vortec roller cam, but I'm still using factory TBI heads with roller tip rocker arms and a modifed factory TBI intake.


    dave w
    I'll look around! And if I can't find it, Jegs has a few different styles of adapters I can use.

  11. #11
    Super Moderator dave w's Avatar
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    Quote Originally Posted by jdyates View Post
    I'll look around! And if I can't find it, Jegs has a few different styles of adapters I can use.
    Based on personal experience, I could not give positive feedback, or recommend using the TBI adapter plate available here. http://www.ebay.com/itm/CHEVY-TBI-FU...cea44c&vxp=mtr

    If it was made from aluminum, then I would think it would be a good product.

    dave w

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