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engine question

Discussion in '1973-1991 K5 Blazer | Truck | Suburban' started by muddysub, Sep 10, 2001.

  1. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    i was reading a post about mounting a tachometer, and i'm gettin one soon, but there's one thing i need to know. where does my 1989 tbi 350 redline at? i've heard 5500, i've heard 8000. none of my friends here know, so i thought i'd ask my smart friends. (you guys)

    what do ya mean " if it ain't broke, don't fix it"?
    scott,
    1989 suburban 3/4t 4" lift soon to be rollin on 36s, tbi350
     
  2. WOODYJ

    WOODYJ 1/2 ton status

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    Boy, 5500 sounds like a big plenty without a bunch of internal engine work. Don't really know for sure but if you try that 8000 trick, you will definitely be fixing it , cause it will be broke!! Just my $.02 worth.

    k5woody I Don't Understand The Jeep Thing Either!!!
     
  3. HarryH3

    HarryH3 1 ton status Author

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    The factory tach on our '94 Sub redlines at 5,000. It's got pretty much the same engine as your '89.

    8 grand isn't gonna happen on a stock engine. The valves will be floating way before you get anywhere near that. [​IMG]

    <font color=black>HarryH3 - '75 K5</font color=black>
    <a target="_blank" href=http://www.angelfire.com/super/ThunderTruck>www.angelfire.com/super/ThunderTruck</a>
    It's a great day to be alive...
     
  4. Nrose07

    Nrose07 1/2 ton status

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    well its not soo much where it safely redlines but where you run out of breath. If you look at a factory tach the yellow starts at 4500 and the red at 5000. The thing is on a high performance motor i.e.( high effiency ) the stock tbi (525cfm) will only support 4500rpm. On a stock motor maybe 5000rpm. Get a 675cfm (big block ) TBI and you will soon enough find out your redline, permantly. But all said and done on a stock short block (cast pistons, cast crank, stock rods) and a GOOD PERFORMANCE balancing job 7000 is the max. and considered reliable.

    Displacement, cubes, and did you say you drive a riceburner???
     
  5. Blazer79

    Blazer79 1/2 ton status

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    If it's never been rebuilt, I don't see a reason to go above 4500 or 5000 at most.

    <font color=purple>//////
    <a target="_blank" href=http://blazer79.freeyellow.com>blazer79.freeyellow.com</a></font color=purple><font color=black>
    Soon a 454 K5!!</font color=black>
    [​IMG]
     
  6. muddysub

    muddysub 1 ton suburban status Staff Member Moderator GMOTM Winner

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    thanks for the info

    what do ya mean " if it ain't broke, don't fix it"?
    scott,
    1989 suburban 3/4t 4" lift soon to be rollin on 36s, tbi350
     
  7. Wheels

    Wheels 1/2 ton status

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    Food for thought...stock harmonic balancer's (torsional dampner) are only rated to 4600 rpm. The elastometer (rubber material) will break down and cause things to go haywire real quick. The elastometer disapates the enegery in the form of heat and it's the heat that causes it to breakdown. We can get deep into this but it's late and it's been a long day.
     
  8. mike reeh

    mike reeh 1/2 ton status

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    I dont care what anyone says, you dont want to take your stock pre-91 V8 to 7000 under any circumstances.. I dont care if you just rebuilt it to factory specs, you're crazy... I wouldnt even take it to 6K.. besides you're not making any good power up that high anyway.. keep it at 5K or less, 4500 is better especially on a motor with some miles.. thats my $0.05 (prices are going up because of the terrorist attacks)
     
  9. Sparky87k5

    Sparky87k5 1/2 ton status

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    There are few 350 truck engines that will make power above 4500 and even fewer that will do the job above 5000. Go higher than that and risk a reduction of said owners bank balance!

    87 K5, D60, 14FF, NV4500 & NP208
    Build it Bulletproof and take it fishing!
     

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