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GM 330hp 350 with a HT383 cam tbi?

Discussion in 'The Garage' started by camok5, Nov 22, 2005.

  1. camok5

    camok5 1/2 ton status Premium Member

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    So I need a new engine soon and it has to work with my tbi. I like the power of the GM 330hp 350 but it makes its power at to high of a rpm and the ht383 costs to much. I emailed turbo city and they said I can put a ht383 cam into a GM 330hp 350 to give it more torque and only lose a little hp on the top end plus it can still be made to work with my tbi. Does anyone know if this seem like a good idea or should I try something else? I dont really want to build my own engine and all the other crate engines seem to cost to much, I know I will have to get a new chip, intake, etc but I already have some of the stuff.
     
  2. RootBreaker

    RootBreaker 3/4 ton status Premium Member

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    I dont have tbi but i too have noticed how expensive this is... even a crate motor isnt gonna be cheap.... if the price on that is good id say go for it...

    so far I have my motor and paid the following for stuff...
    $255 cam - new
    $118 vortec intake - new
    $200 vortec heads - used
    $125 rings - new
    $??? Rod Bearings - dont remember how much I paid but had them for a while

    still need to buy gaskets
    1991 caprice lower gasket set - $75
    1997 tahoe upper gasket set - $55
    vortec intake bolts - $20

    then i can tag on the
    $419 for my holley truck avenger - paid that much as i got it when it came out

    nice thing is i dont need a chip as i dont have one.. but either way... power plus cheap is not in the dictionary....

    good luck in deciding....

    oh yeah... also to loose some hp isnt that big of a deal when you get an optimal setup....

    I was going to go with a comp cams xtreme 4x4 cam with .474 lift but the rpms were 1200-5000+
    but instead went with comp cams xtreme 4x4 cam with .458 lift and it is idle - 5000

    so i estimated with desktop dyno 2003 ... and my setup with both cams
    .474 lift = 355hp/465lb-ft torque
    .458 lift = 325hp/445lb-ft torque

    but still over my current
    .403 lift = 195hp/295lb-ft torque
     
  3. beastofablaze

    beastofablaze 1/2 ton status

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    When people say there is no replacement for displacement...I start to wonder if they'ev ever heard of money.

    If its torque your looking for a smallblock can fill the void but it will cost you.

    I just finished putting together my tbi 355 and desktop dyno says my sb will be making more torque off idle than a stock 454. dd estimated my motor at 375 hp and 410 ft lbs of torque with 404 ft lbs at 2000 rpm. In real life i'd say it'll be making 355 hp and 400 ft lbs but i've found dd can be dead wrong or get it right on the nose.

    First things first... can your tbi setup handle 330 hp? Unless you have a larger tbi it won't.

    If you need to get a bigger tbi it'll cost you 200 for the cheapest "new" one you can get... you'll find a lot of remanufacture and bored out sb and bb tbi's on ebay.

    The cam out of a 383 is not the best cam for tq in a 350. Cams have come a long way... check out crane cams zcam... you'll make alot of hp with sacrificing any tq. something like this...

    duration: 256 int/268 exhaust Lift:.432 int/.459 exhaust. 1200-5200 rpm.

    I would bet this cam makes more tq and more hp than the ht383 cam.

    Also what do you mean you don't want to put together your own motor? Would heads be too much? one of the best options is to buy a good shortblock and swap some good heads on it. you'll find that is ONE of the best ways for you to get power for your dollar. Although with tbi you really can't make any more power than 375 hp... as far as tq it goes a lot higher but if you do the shortblock thing make sure you don't build a motor that will be making too much power for tbi because if you starve a motor it will overheat, damage plugs, etc.

    good luck.
     
  4. 1-ton

    1-ton 1/2 ton status Premium Member

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    You might want TurboCity to clarify what they mean by this. Your factory TBI unit is probobaly only capable of flowing 450 CFM. This is not enough for a 300 + HP engine. They may be talking about modifying your TBI unit, which will cost some money. It takes a lot of modifications (modifications = money) to get TBI to work with any engine over 275 HP.
     
  5. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I don't think it would be that hard. Stock 2" 454 TBI with stock 80# injectors and 93-94 (IIRC?) 30 psi in tank pump should feed it ok with a new chip.

    I'm just getting started in this TBI tuning thing and I'm pretty amazed at what is possible. For my mild roller camed 350 I've added a bored TBI running at 14 psi with a new chip, soon to go to 20+psi as soon as I get the new pump installed (the stock SBC pump can't even hold 14 psi reliably). But if you don't want to get into burning your own chips, your going to be very limited in what you can do…
     
  6. beastofablaze

    beastofablaze 1/2 ton status

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    well your looking at 500 bucks at least to get your tbi capable of 300 plus hp, if you don't have the right setup already. whether you get a chip burned or do it yourself it'll cost you. If he doesn't want to build his motor i doubt he wants to burn his own chips.

    But you never know...
     
  7. 1-ton

    1-ton 1/2 ton status Premium Member

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    What software are you using, and are you using an EPROM burner?
     
  8. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    I was using WinALDL for general diagnostics and tuning (i.e. engine tuning, not chip). Has worked well for several years just for general stuff and total cost to build the cable was about $10-15.

    For the new chip and real tuning work I'm working on now, I'm using TunerPro RT with the AutoProm (Moats.net) and a modified ECM (24 pin converted to 28 pin) and AT29C256 EEPROM chip (with ZIF while I'm working on it). Problem is, TunerPro RT can't datalog on the 160 baud 7747, but Craig is working on a firmware fix to correct that. So, in order to do "real time emulation" with "real time data logging" I'm going to have to use WinALDL along with the TunerPro RT for now. Once I'm done tuning, I'll burn a chip and remove the ZIF so I can close up the ECM case again...
     
  9. beastofablaze

    beastofablaze 1/2 ton status

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    Ok... sorry for the hijack but this is really good info... I'm waiting on my prominator and i figured i should get familar with the software so i tried to download the 7747 .bin and when i opened it up it just plain didn't work. Why is this?
     
  10. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    No idea. But this already going way OT, so probably better to ask on ThirdGen anyway along with more info such as what you are "opening" it in, what def file, and so on...
     
  11. camok5

    camok5 1/2 ton status Premium Member

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    I already have a larger cfm-tech thottle body and pressure regulator, and I,m aware that I will need a chip burned and larger injectors. The reason I dont want to build my own is because of time and I need to know it will work with a tbi( its my daily driver) without any problems or down time. Also I know people running the 330hp engine with tbi and they say that it needs more low end power. I am not looking for tons of power just more than the factory ones and cheaper than a 383 crate engine. I really want to know if the ht383 cam sounds like a good idea or should I try something else that will work with my tbi and still be cost efficient?
     
  12. dyeager535

    dyeager535 1 ton status Premium Member

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    If you want low end, generally stick with a "small" cam. You are going to end up sacrificing at least some low end for top end, or vice versa.

    The smaller cams are going to be easier to get to work with TBI as well.
     
  13. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    Yes, and most of us will appreciate an engine built for low end much more than high end. About the only exception are people going for low ETs, mud junkies, and sand fanatics. Then, choose all parts to work well together and forget about HP numbers. "Seat of the pants power" and "general purpose fun" are much more about low rpm torque than HP (just a function of torque and rpm) anyway. And the added bene of good low rpm torque will be better gas mileage and less stress on many parts that will often be cheaper to start with.
     
  14. 1-ton

    1-ton 1/2 ton status Premium Member

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    To clarify: Does this mean you are using a 28 pin AT29C256 EEPROM, with a 28 pin to 24 pin ZIF adapter?

    That sucks because the 7747 ECM was the most widely used ECM General Motors had...used in vehicles from the 4.3 Liter V6 to the Big Block 454.

    I went to moats.net and saw there PROM Burner. They also have a USB to ALDL adapter that looks pretty cool.
     
  15. BadDog

    BadDog SOL Staff Member Super Moderator Author

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    No, I have a standard 28 pin ZIF that plugs into my 28->24 pin adapter. That way I can remove the ZIF when I'm done and plug in the 28 pin EEPROM.

    It does data log in "hardware" mode, but you can't emulate while data logging at the same time. He's working on the fix now. But to be fair, the focus has generally been on the vastly superior later ECMs rather than the slow and limited 7747, which was used on lots of trucks and other stuff, but generally not the hipo stuff that are more frequently "tuned". In fact, a lot of discussion has occurred all over the net on the benefits of "upgrading" ECMs and techniques to do so.
     

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