Removing 7.4 Vortech from my 1999 K2500 suburban

Discussion in 'Engine Performance + Maintenance' started by Saab84mw, Mar 7, 2020.

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  1. Saab84mw

    Saab84mw Newbie

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    Finally got the truck back to the house now getting ready to pull the engine for a rebuild.

    Looking for any thoughts or tips with pulling this engine haven’t done this one before this engine is partially froze up still turns over but not very well. Like somethings I should or should not do while in the process of pulling this motor.

    And maybe some things I need to do before I put the rebuilt engine back in.

    My plan is to have the machine shop rebuild the engine into long block form with a mild towing cam upgraded springs and that’s about it.
     
  2. L29Sub

    L29Sub I'm Awesome

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    Recommend not turning it more than necessary to remove the converter bolts.
    There's boatloads of parts for 7.4 Vortec laying around. Weigh costs of new against machine shop charges. 'Course, if a shop is rebuilding it for you, I'd give them a limited 'carte blanche' to keep them happy...and their warranty in good standing.
    Be careful with charges. You may find a long crate cheaper than a local repair. Crates are high quality items also. Usually. GM definitely is good. They'll offer tow setups and some custom specs.
    Until you see what's damaged, no way to assess where you are.
    Unless you plan major tuning, with headers, ECM and intake mods, be careful with cam choice.
    '97 ECM is limited. Carbs are not.
    Ideas below. Note the sophisticated dyno...[​IMG]

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  3. Saab84mw

    Saab84mw Newbie

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    Nice engine but I’m kind of working on a budget I’ve been milking this engine for the past two years knew it was getting kind of tired so now I have to replace it.

    so been doing a lot of research on it and was going to go with a rebuilt long block from Jasper engines for the GEN six they wanted about $3300 that was that shop cost and a stock engine no modifications.

    so reading the forum and talking to some of my SCCA racing buddies here locally I found a recommended machine shop went and talk to the guy about what I want to do to the engine wanted to keep it simple keep the fuel injection and just put a mild cam in it I’ll try to post a picture of the specifications on the cam all he said I need to do is put a new valve springs in it to match the lift on the cam. And this cam was his recommendation because I didn’t want to do too much to the engine might do some tuning later on and put some headers on later on when the budget gets a little better. Would still like to delete EGR before I put the headers on if possible and maybe do a 411 computer swap.

    The machine shop will do the long block for $2800 and I just buy the cam in the springs and he installs everything for that price with a warranty

    24FBB35E-3C57-4087-8F7B-D5BE29CAB444.png
     
  4. Supercharged111

    Supercharged111 I'm Awesome

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    I put a bigger cam in mine than that. The one thing I'll say is it's a tight fit and you'll have to finagle it past the motor mounts to get it out.
     
  5. L29Sub

    L29Sub I'm Awesome

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    Be sure the builder understands 7.4 rockers cannot be adjusted. And the stock valve covers are low profile and cannot be changed for taller due to the throttle body location.
    If the cam instructions state that the cam fits '96-'99 Vortec 7.4 in a Chebby truck without further mods, so be it.
    It can be converted to adjustable if necessary.
    A lot of torque cams interchange with Mercruiser 7.4, which has entirely different FI and plenum.



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  6. L29Sub

    L29Sub I'm Awesome

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    Looking at the cam specs says that the idle is going to be a bit rumpy at standard 7.4 idle speeds. I didn't look at the profiles, but your typical use will be 1500 3000 RPM. You'll want to see a torque spike around 2k or a bit lower. 60 mph is about 2k with a 4:10?
    The HP curve is not what you want to concern with...torque is what you'll feel at useable speeds. Especially so if you tow anything.
    Post the dyno graphs. They tell the story.

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  7. L29Sub

    L29Sub I'm Awesome

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    Good Comp Cam specs for street. [​IMG]

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  8. Saab84mw

    Saab84mw Newbie

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    When I called comp cams about a cam suggestion they suggested the extreme energy cam which would require a computer tune adjustable rocker arms springs new rollers and everything that was a little too much for what I want to do.

    when I was talking to the machine shop they suggested against doing adjustable rocker arms that’s the reason why we picked the cam we did it’s not required and it would be under the stock about covers all I need is a new springs for the over 500 he said.
     
  9. Saab84mw

    Saab84mw Newbie

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    You are about right on the RPMs I run about 2500 RPMs at 70 miles an hour runs about 2200 RPMs at 60 miles an hour. That is running a tire size of 265/ 75/16 on stock factory wheels.

    Yes I mainly use this truck for towing my travel trailer it is 28 foot with a max weight of about 6500 pounds towed it very well even with the weak engine.

    my goal here is to make a reliable tow vehicle so I can travel up to Canada with it without any issues.

    by the way the transmission and transfer case was replaced about two years ago with reman units.
     
  10. SPDMETL

    SPDMETL Newbie

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    GM sells a 488 direct replacement for this...with a warranty. Find the money!
     

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