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Thread: I want more from my 454

  1. #1
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    I want more from my 454

    Hello. I've been reading the forum for a couple of months now I decided to stick my toe in and post a question to you folks.
    I have a 1991 1 Ton Extended Cab dually with a 454, auto trans, and a 4.10 diff. It has 72,000 miles and is stock except for a Magnaflow muffler, a Hypertech chip, a K&N filter in the stock housing, and I removed the cone-shaped restriction from the oval plastic intake noise damper (it is now essentially a wide open shot to the mouth of the TBI). The truck runs good. However, my previous truck, a 1979 C2500 with a 350 cubic inch engine and a 4.10 diff was peppier. Much peppier.
    My wife is talking about a trailer and I'd like for this 454 to have some more muscle before I hang a trailer on it.
    Also, the truck has to pass Calif emissions.

    Thank you in advance for any advice you may have.

    Don
    Don

    1968 Chevy El Camino
    1991 Chevy C3500 Dually

  2. #2
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    its expensive but maybe a larger throttle body and headers? i`m going through the same thing on my 98 454 vortec, headers made bottom end tourque difference, still waiting for my oversized throttle body in mail, but may cam it and re-flow the heads, waiting for true cold air intake kit aswell, i may have to resize my injectors after the head work though, all fun and games!!

  3. #3
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    have you reworked the tbi
    Shave the lips off around the bores
    TBI CHIPS shows what im talking about
    Last edited by jarhead2001; 03-17-2008 at 05:57 PM. Reason: more info

  4. #4
    Senior Member Sneakysportsman's Avatar
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    HOLD UP WAIT A MINUTE! LET PUT A LITTLE INFO IN IT!
    I have been fooling with a tbi set up for over a year now. A chip will help a little, bolt on items will help to a degree or 2. But when you start improving flow characteristics of a computer controlled engine you are asking for it.
    Lets study Class is in session,
    A 454 is a beast, for sure, the ECM will controll the parameters for air-fuel ratio, vaccum timing advance and so on.
    I started out with "I want just a little more, I want to drive every day but turn heads."
    Heres where it started, Vortec Heads, opened valves to 2.02, 1.60.
    Already to much flow for stock TBI unit, stock heads are pushing the limit on flow ratios for fuel delivery.
    Next 750 cfm TB unit, then 1 5/8 headers, Edelbrock LG4 TBI cam-is good for stock engine, not where I am already. Then the Edelbrock Air Gap intake look really good, whata ya know, I even found a TBI adapter plate for the intake.
    When crank up comes along, it is so lean that it won't even take ANY throttle.
    I paid a guy $300.00 to sit in passenger side and program ECM.
    After program was finished @ 30mph it would shift down to 1st and roll the back tires. Worked well for a week- burn't the driver out that controlls the injectors. Replaced the computer 3 times. Finally switched to a TPI, Couldn.t get it to idle or run at low rpm. Pulled engine and tuned down to smaller cam, but still is too lean. I am currently customizing a chip to run the engine, myself.
    You can do some minor things, BUT not much.
    My suggest,
    You have a chip- leave the TBI unit alone put in a cam and headers that was designed for that engine. The reason is you can remove the chip and still pass emisions and the engine will run fine while the chip is out.
    All the little thing eventually add up. I only wanted to move up from approx 200 hp to maybe 240-250. But have ended up with 340hp and 14.7 mpg on pump 93.

  5. #5
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    this is my 3rd tbi truck I agree leave the heads alone but the tbi is so restricted that on all 3 (89 350, 92 and a 94 350 tbi) with minor tbi work removing the ridges around the bores, injector pod spacer that I could see a diferance in fuel econamy and IMO seemed to help when towing, never ran headers just a good exhaust single 2.5 is plenty for our low rpm on a 350 the 454 id use 3" due to the volume.

  6. #6
    Senior Member Sneakysportsman's Avatar
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    The tbi I use is a 2" bore, where a stock is 1 11/16".Stock flow is 420 on small block, but 600 on BB.

  7. #7
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    I took a different path, I have a 87 CC Dually, and was getting a larger trailer, I went to the edelbrock port injection from the TBI system, along with headers, truck has ton more pulling power and MPG stayed the same as when I towed a trailer 3 times lighter ...

  8. #8
    Senior Member Sneakysportsman's Avatar
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    That my friend is a good Idea. If I recall that system comes with a pre-program chip. This is a A+ upgrade. Best bang for the buck and you won't need a ton of headache pills.

  9. #9
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    Thank you all. I will check out the Edelbrock injection system and look into having my exhaust upgraded (larger diameter and more efficient y-pipe).

    Don
    Don

    1968 Chevy El Camino
    1991 Chevy C3500 Dually

  10. #10
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    I just had another thought (my quota for the day...). Would the installation of a shift kit in the trans give me the illusion of more muscle or make the truck more responsive to the throttle?

    Thank you,
    Don
    Don

    1968 Chevy El Camino
    1991 Chevy C3500 Dually

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